October 2022 - Linux-stable-mirror

FAILED: patch "[PATCH] serial: stm32: Deassert Transmit Enable on ->rs485_config()" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: adafbbf6895e ("serial: stm32: Deassert Transmit Enable on ->rs485_config()") d7c76716169d ("serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 mode") 3bcea529b295 ("serial: stm32: Factor out GPIO RTS toggling into separate function") 037b91ec7729 ("serial: stm32: fix software flow control transfer") 2a3bcfe03725 ("serial: stm32: fix flow control transfer in DMA mode") 33bb2f6ac308 ("serial: stm32: rework RX over DMA") cc58d0a3f0a4 ("serial: stm32: re-introduce an irq flag condition in usart_receive_chars") 2aa1bbb21f26 ("serial: stm32: add FIFO threshold configuration") cea37afd28f1 ("serial: stm32: defer sysrq processing") e359b4411c28 ("serial: stm32: fix threaded interrupt handling") 3d530017bef1 ("serial: stm32: update wakeup IRQ management") 3db1d52466dc ("serial: stm32: fix tx_empty condition") 12761869f0ef ("serial: stm32: fix wake-up flag handling") ad7676812437 ("serial: stm32: fix a deadlock condition with wakeup event") 25a8e7611da5 ("serial: stm32: fix TX and RX FIFO thresholds") f4518a8a75f5 ("serial: stm32: fix startup by enabling usart for reception") 87fd0741d6dc ("serial: stm32: fix probe and remove order for dma") a99163e9e708 ("Merge tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From adafbbf6895eb0ce41a313c6ee68870ab9aa93cd Mon Sep 17 00:00:00 2001 From: Lukas Wunner <lukas(a)wunner.de> Date: Sun, 11 Sep 2022 11:02:03 +0200 Subject: [PATCH] serial: stm32: Deassert Transmit Enable on ->rs485_config() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The STM32 USART can control RS-485 Transmit Enable in hardware. Since commit 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control"), it can alternatively be controlled in software. That was done to allow RS-485 even if the RTS pin is unavailable because it's pinmuxed to a different function. However the commit neglected to deassert Transmit Enable upon invocation of the ->rs485_config() callback. Fix it. Avoid forward declarations by moving stm32_usart_tx_empty(), stm32_usart_rs485_rts_enable() and stm32_usart_rs485_rts_disable() further up in the driver. Fixes: 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control") Cc: stable(a)vger.kernel.org # v5.9+ Cc: Marek Vasut <marex(a)denx.de> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Signed-off-by: Lukas Wunner <lukas(a)wunner.de> Link: https://lore.kernel.org/r/6059eab35dba394468335ef640df8b0050fd9dbd.16628866… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 0b18615b2ca4..c48f225eba86 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -131,6 +131,53 @@ static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits) writel_relaxed(val, port->membase + reg); } +static unsigned int stm32_usart_tx_empty(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC) + return TIOCSER_TEMT; + + return 0; +} + +static void stm32_usart_rs485_rts_enable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + if (stm32_port->hw_flow_control || + !(rs485conf->flags & SER_RS485_ENABLED)) + return; + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } +} + +static void stm32_usart_rs485_rts_disable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + if (stm32_port->hw_flow_control || + !(rs485conf->flags & SER_RS485_ENABLED)) + return; + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } +} + static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE, u32 delay_DDE, u32 baud) { @@ -214,6 +261,12 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + /* Adjust RTS polarity in case it's driven in software */ + if (stm32_usart_tx_empty(port)) + stm32_usart_rs485_rts_disable(port); + else + stm32_usart_rs485_rts_enable(port); + return 0; } @@ -529,42 +582,6 @@ static void stm32_usart_tc_interrupt_disable(struct uart_port *port) stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE); } -static void stm32_usart_rs485_rts_enable(struct uart_port *port) -{ - struct stm32_port *stm32_port = to_stm32_port(port); - struct serial_rs485 *rs485conf = &port->rs485; - - if (stm32_port->hw_flow_control || - !(rs485conf->flags & SER_RS485_ENABLED)) - return; - - if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl | TIOCM_RTS); - } else { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl & ~TIOCM_RTS); - } -} - -static void stm32_usart_rs485_rts_disable(struct uart_port *port) -{ - struct stm32_port *stm32_port = to_stm32_port(port); - struct serial_rs485 *rs485conf = &port->rs485; - - if (stm32_port->hw_flow_control || - !(rs485conf->flags & SER_RS485_ENABLED)) - return; - - if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl & ~TIOCM_RTS); - } else { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl | TIOCM_RTS); - } -} - static void stm32_usart_transmit_chars_pio(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); @@ -807,17 +824,6 @@ static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) return IRQ_HANDLED; } -static unsigned int stm32_usart_tx_empty(struct uart_port *port) -{ - struct stm32_port *stm32_port = to_stm32_port(port); - const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - - if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC) - return TIOCSER_TEMT; - - return 0; -} - static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct stm32_port *stm32_port = to_stm32_port(port);

2 years, 2 months

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FAILED: patch "[PATCH] serial: stm32: Deassert Transmit Enable on ->rs485_config()" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: adafbbf6895e ("serial: stm32: Deassert Transmit Enable on ->rs485_config()") d7c76716169d ("serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 mode") 3bcea529b295 ("serial: stm32: Factor out GPIO RTS toggling into separate function") 037b91ec7729 ("serial: stm32: fix software flow control transfer") 2a3bcfe03725 ("serial: stm32: fix flow control transfer in DMA mode") 33bb2f6ac308 ("serial: stm32: rework RX over DMA") cc58d0a3f0a4 ("serial: stm32: re-introduce an irq flag condition in usart_receive_chars") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From adafbbf6895eb0ce41a313c6ee68870ab9aa93cd Mon Sep 17 00:00:00 2001 From: Lukas Wunner <lukas(a)wunner.de> Date: Sun, 11 Sep 2022 11:02:03 +0200 Subject: [PATCH] serial: stm32: Deassert Transmit Enable on ->rs485_config() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The STM32 USART can control RS-485 Transmit Enable in hardware. Since commit 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control"), it can alternatively be controlled in software. That was done to allow RS-485 even if the RTS pin is unavailable because it's pinmuxed to a different function. However the commit neglected to deassert Transmit Enable upon invocation of the ->rs485_config() callback. Fix it. Avoid forward declarations by moving stm32_usart_tx_empty(), stm32_usart_rs485_rts_enable() and stm32_usart_rs485_rts_disable() further up in the driver. Fixes: 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control") Cc: stable(a)vger.kernel.org # v5.9+ Cc: Marek Vasut <marex(a)denx.de> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Signed-off-by: Lukas Wunner <lukas(a)wunner.de> Link: https://lore.kernel.org/r/6059eab35dba394468335ef640df8b0050fd9dbd.16628866… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 0b18615b2ca4..c48f225eba86 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -131,6 +131,53 @@ static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits) writel_relaxed(val, port->membase + reg); } +static unsigned int stm32_usart_tx_empty(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + + if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC) + return TIOCSER_TEMT; + + return 0; +} + +static void stm32_usart_rs485_rts_enable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + if (stm32_port->hw_flow_control || + !(rs485conf->flags & SER_RS485_ENABLED)) + return; + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } +} + +static void stm32_usart_rs485_rts_disable(struct uart_port *port) +{ + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + + if (stm32_port->hw_flow_control || + !(rs485conf->flags & SER_RS485_ENABLED)) + return; + + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } +} + static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE, u32 delay_DDE, u32 baud) { @@ -214,6 +261,12 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + /* Adjust RTS polarity in case it's driven in software */ + if (stm32_usart_tx_empty(port)) + stm32_usart_rs485_rts_disable(port); + else + stm32_usart_rs485_rts_enable(port); + return 0; } @@ -529,42 +582,6 @@ static void stm32_usart_tc_interrupt_disable(struct uart_port *port) stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE); } -static void stm32_usart_rs485_rts_enable(struct uart_port *port) -{ - struct stm32_port *stm32_port = to_stm32_port(port); - struct serial_rs485 *rs485conf = &port->rs485; - - if (stm32_port->hw_flow_control || - !(rs485conf->flags & SER_RS485_ENABLED)) - return; - - if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl | TIOCM_RTS); - } else { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl & ~TIOCM_RTS); - } -} - -static void stm32_usart_rs485_rts_disable(struct uart_port *port) -{ - struct stm32_port *stm32_port = to_stm32_port(port); - struct serial_rs485 *rs485conf = &port->rs485; - - if (stm32_port->hw_flow_control || - !(rs485conf->flags & SER_RS485_ENABLED)) - return; - - if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl & ~TIOCM_RTS); - } else { - mctrl_gpio_set(stm32_port->gpios, - stm32_port->port.mctrl | TIOCM_RTS); - } -} - static void stm32_usart_transmit_chars_pio(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); @@ -807,17 +824,6 @@ static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) return IRQ_HANDLED; } -static unsigned int stm32_usart_tx_empty(struct uart_port *port) -{ - struct stm32_port *stm32_port = to_stm32_port(port); - const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - - if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC) - return TIOCSER_TEMT; - - return 0; -} - static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct stm32_port *stm32_port = to_stm32_port(port);

2 years, 2 months

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FAILED: patch "[PATCH] xen/gntdev: Accommodate VMA splitting" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 5c13a4a0291b ("xen/gntdev: Accommodate VMA splitting") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") 30dcc56bba91 ("xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests") 970655aa9b42 ("xen/gntdev: fix gntdev_mmap() error exit path") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") 9293724192a7 ("xen/gntdev: Do not use mm notifiers with autotranslating guests") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") ee7f5225dc3c ("xen: Stop abusing DT of_dma_configure API") bce5963bcb4f ("xen/events: fix binding user event channels to cpus") 8b1e0f81fb6f ("mm/pgtable: drop pgtable_t variable from pte_fn_t functions") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:06 -0400 Subject: [PATCH] xen/gntdev: Accommodate VMA splitting Prior to this commit, the gntdev driver code did not handle the following scenario correctly with paravirtualized (PV) Xen domains: * User process sets up a gntdev mapping composed of two grant mappings (i.e., two pages shared by another Xen domain). * User process munmap()s one of the pages. * User process munmap()s the remaining page. * User process exits. In the scenario above, the user process would cause the kernel to log the following messages in dmesg for the first munmap(), and the second munmap() call would result in similar log messages: BUG: Bad page map in process doublemap.test pte:... pmd:... page:0000000057c97bff refcount:1 mapcount:-1 \ mapping:0000000000000000 index:0x0 pfn:... ... page dumped because: bad pte ... file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0 ... Call Trace: <TASK> dump_stack_lvl+0x46/0x5e print_bad_pte.cold+0x66/0xb6 unmap_page_range+0x7e5/0xdc0 unmap_vmas+0x78/0xf0 unmap_region+0xa8/0x110 __do_munmap+0x1ea/0x4e0 __vm_munmap+0x75/0x120 __x64_sys_munmap+0x28/0x40 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x61/0xcb ... For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG) would print out the following and trigger a general protection fault in the affected Xen PV domain: (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... As of this writing, gntdev_grant_map structure's vma field (referred to as map->vma below) is mainly used for checking the start and end addresses of mappings. However, with split VMAs, these may change, and there could be more than one VMA associated with a gntdev mapping. Hence, remove the use of map->vma and rely on map->pages_vm_start for the original start address and on (map->count << PAGE_SHIFT) for the original mapping size. Let the invalidate() and find_special_page() hooks use these. Also, given that there can be multiple VMAs associated with a gntdev mapping, move the "mmu_interval_notifier_remove(&map->notifier)" call to the end of gntdev_put_map, so that the MMU notifier is only removed after the closing of the last remaining VMA. Finally, use an atomic to prevent inadvertent gntdev mapping re-use, instead of using the map->live_grants atomic counter and/or the map->vma pointer (the latter of which is now removed). This prevents the userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the same address range as a previously set up gntdev mapping. This scenario can be summarized with the following call-trace, which was valid prior to this commit: mmap gntdev_mmap mmap (repeat mmap with MAP_FIXED over the same address range) gntdev_invalidate unmap_grant_pages (sets 'being_removed' entries to true) gnttab_unmap_refs_async unmap_single_vma gntdev_mmap (maps the shared pages again) munmap gntdev_invalidate unmap_grant_pages (no-op because 'being_removed' entries are true) unmap_single_vma (For PV domains, Xen reports that a granted page is being unmapped and triggers a general protection fault in the affected domain, if Xen was built with CONFIG_DEBUG) The fix for this last scenario could be worth its own commit, but we opted for a single commit, because removing the gntdev_grant_map structure's vma field requires guarding the entry to gntdev_mmap(), and the live_grants atomic counter is not sufficient on its own to prevent the mmap() over a pre-existing mapping. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h index 40ef379c28ab..9c286b2a1900 100644 --- a/drivers/xen/gntdev-common.h +++ b/drivers/xen/gntdev-common.h @@ -44,9 +44,10 @@ struct gntdev_unmap_notify { }; struct gntdev_grant_map { + atomic_t in_use; struct mmu_interval_notifier notifier; + bool notifier_init; struct list_head next; - struct vm_area_struct *vma; int index; int count; int flags; diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index eb0586b9767d..4d9a3050de6a 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -286,6 +286,9 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) */ } + if (use_ptemod && map->notifier_init) + mmu_interval_notifier_remove(&map->notifier); + if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); @@ -298,7 +301,7 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) { struct gntdev_grant_map *map = data; - unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; + unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | (1 << _GNTMAP_guest_avail0); u64 pte_maddr; @@ -508,11 +511,7 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); - if (use_ptemod) { - WARN_ON(map->vma != vma); - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } + vma->vm_private_data = NULL; gntdev_put_map(priv, map); } @@ -540,29 +539,30 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn, struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; + unsigned long map_start, map_end; if (!mmu_notifier_range_blockable(range)) return false; + map_start = map->pages_vm_start; + map_end = map->pages_vm_start + (map->count << PAGE_SHIFT); + /* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ - if (map->vma->vm_start >= range->end || - map->vma->vm_end <= range->start) + if (map_start >= range->end || map_end <= range->start) return true; - mstart = max(range->start, map->vma->vm_start); - mend = min(range->end, map->vma->vm_end); + mstart = max(range->start, map_start); + mend = min(range->end, map_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", - map->index, map->count, - map->vma->vm_start, map->vma->vm_end, - range->start, range->end, mstart, mend); - unmap_grant_pages(map, - (mstart - map->vma->vm_start) >> PAGE_SHIFT, - (mend - mstart) >> PAGE_SHIFT); + map->index, map->count, map_start, map_end, + range->start, range->end, mstart, mend); + unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, + (mend - mstart) >> PAGE_SHIFT); return true; } @@ -1042,18 +1042,15 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) return -EINVAL; pr_debug("map %d+%d at %lx (pgoff %lx)\n", - index, count, vma->vm_start, vma->vm_pgoff); + index, count, vma->vm_start, vma->vm_pgoff); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; - if (use_ptemod && map->vma) - goto unlock_out; - if (atomic_read(&map->live_grants)) { - err = -EAGAIN; + if (!atomic_add_unless(&map->in_use, 1, 1)) goto unlock_out; - } + refcount_inc(&map->users); vma->vm_ops = &gntdev_vmops; @@ -1074,15 +1071,16 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) map->flags |= GNTMAP_readonly; } + map->pages_vm_start = vma->vm_start; + if (use_ptemod) { - map->vma = vma; err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); - if (err) { - map->vma = NULL; + if (err) goto out_unlock_put; - } + + map->notifier_init = true; } mutex_unlock(&priv->lock); @@ -1099,7 +1097,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) */ mmu_interval_read_begin(&map->notifier); - map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); @@ -1128,13 +1125,8 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) out_unlock_put: mutex_unlock(&priv->lock); out_put_map: - if (use_ptemod) { + if (use_ptemod) unmap_grant_pages(map, 0, map->count); - if (map->vma) { - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } - } gntdev_put_map(priv, map); return err; }

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] xen/gntdev: Accommodate VMA splitting" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 5c13a4a0291b ("xen/gntdev: Accommodate VMA splitting") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") 30dcc56bba91 ("xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests") 970655aa9b42 ("xen/gntdev: fix gntdev_mmap() error exit path") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") 9293724192a7 ("xen/gntdev: Do not use mm notifiers with autotranslating guests") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") ee7f5225dc3c ("xen: Stop abusing DT of_dma_configure API") bce5963bcb4f ("xen/events: fix binding user event channels to cpus") 8b1e0f81fb6f ("mm/pgtable: drop pgtable_t variable from pte_fn_t functions") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:06 -0400 Subject: [PATCH] xen/gntdev: Accommodate VMA splitting Prior to this commit, the gntdev driver code did not handle the following scenario correctly with paravirtualized (PV) Xen domains: * User process sets up a gntdev mapping composed of two grant mappings (i.e., two pages shared by another Xen domain). * User process munmap()s one of the pages. * User process munmap()s the remaining page. * User process exits. In the scenario above, the user process would cause the kernel to log the following messages in dmesg for the first munmap(), and the second munmap() call would result in similar log messages: BUG: Bad page map in process doublemap.test pte:... pmd:... page:0000000057c97bff refcount:1 mapcount:-1 \ mapping:0000000000000000 index:0x0 pfn:... ... page dumped because: bad pte ... file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0 ... Call Trace: <TASK> dump_stack_lvl+0x46/0x5e print_bad_pte.cold+0x66/0xb6 unmap_page_range+0x7e5/0xdc0 unmap_vmas+0x78/0xf0 unmap_region+0xa8/0x110 __do_munmap+0x1ea/0x4e0 __vm_munmap+0x75/0x120 __x64_sys_munmap+0x28/0x40 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x61/0xcb ... For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG) would print out the following and trigger a general protection fault in the affected Xen PV domain: (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... As of this writing, gntdev_grant_map structure's vma field (referred to as map->vma below) is mainly used for checking the start and end addresses of mappings. However, with split VMAs, these may change, and there could be more than one VMA associated with a gntdev mapping. Hence, remove the use of map->vma and rely on map->pages_vm_start for the original start address and on (map->count << PAGE_SHIFT) for the original mapping size. Let the invalidate() and find_special_page() hooks use these. Also, given that there can be multiple VMAs associated with a gntdev mapping, move the "mmu_interval_notifier_remove(&map->notifier)" call to the end of gntdev_put_map, so that the MMU notifier is only removed after the closing of the last remaining VMA. Finally, use an atomic to prevent inadvertent gntdev mapping re-use, instead of using the map->live_grants atomic counter and/or the map->vma pointer (the latter of which is now removed). This prevents the userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the same address range as a previously set up gntdev mapping. This scenario can be summarized with the following call-trace, which was valid prior to this commit: mmap gntdev_mmap mmap (repeat mmap with MAP_FIXED over the same address range) gntdev_invalidate unmap_grant_pages (sets 'being_removed' entries to true) gnttab_unmap_refs_async unmap_single_vma gntdev_mmap (maps the shared pages again) munmap gntdev_invalidate unmap_grant_pages (no-op because 'being_removed' entries are true) unmap_single_vma (For PV domains, Xen reports that a granted page is being unmapped and triggers a general protection fault in the affected domain, if Xen was built with CONFIG_DEBUG) The fix for this last scenario could be worth its own commit, but we opted for a single commit, because removing the gntdev_grant_map structure's vma field requires guarding the entry to gntdev_mmap(), and the live_grants atomic counter is not sufficient on its own to prevent the mmap() over a pre-existing mapping. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h index 40ef379c28ab..9c286b2a1900 100644 --- a/drivers/xen/gntdev-common.h +++ b/drivers/xen/gntdev-common.h @@ -44,9 +44,10 @@ struct gntdev_unmap_notify { }; struct gntdev_grant_map { + atomic_t in_use; struct mmu_interval_notifier notifier; + bool notifier_init; struct list_head next; - struct vm_area_struct *vma; int index; int count; int flags; diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index eb0586b9767d..4d9a3050de6a 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -286,6 +286,9 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) */ } + if (use_ptemod && map->notifier_init) + mmu_interval_notifier_remove(&map->notifier); + if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); @@ -298,7 +301,7 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) { struct gntdev_grant_map *map = data; - unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; + unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | (1 << _GNTMAP_guest_avail0); u64 pte_maddr; @@ -508,11 +511,7 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); - if (use_ptemod) { - WARN_ON(map->vma != vma); - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } + vma->vm_private_data = NULL; gntdev_put_map(priv, map); } @@ -540,29 +539,30 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn, struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; + unsigned long map_start, map_end; if (!mmu_notifier_range_blockable(range)) return false; + map_start = map->pages_vm_start; + map_end = map->pages_vm_start + (map->count << PAGE_SHIFT); + /* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ - if (map->vma->vm_start >= range->end || - map->vma->vm_end <= range->start) + if (map_start >= range->end || map_end <= range->start) return true; - mstart = max(range->start, map->vma->vm_start); - mend = min(range->end, map->vma->vm_end); + mstart = max(range->start, map_start); + mend = min(range->end, map_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", - map->index, map->count, - map->vma->vm_start, map->vma->vm_end, - range->start, range->end, mstart, mend); - unmap_grant_pages(map, - (mstart - map->vma->vm_start) >> PAGE_SHIFT, - (mend - mstart) >> PAGE_SHIFT); + map->index, map->count, map_start, map_end, + range->start, range->end, mstart, mend); + unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, + (mend - mstart) >> PAGE_SHIFT); return true; } @@ -1042,18 +1042,15 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) return -EINVAL; pr_debug("map %d+%d at %lx (pgoff %lx)\n", - index, count, vma->vm_start, vma->vm_pgoff); + index, count, vma->vm_start, vma->vm_pgoff); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; - if (use_ptemod && map->vma) - goto unlock_out; - if (atomic_read(&map->live_grants)) { - err = -EAGAIN; + if (!atomic_add_unless(&map->in_use, 1, 1)) goto unlock_out; - } + refcount_inc(&map->users); vma->vm_ops = &gntdev_vmops; @@ -1074,15 +1071,16 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) map->flags |= GNTMAP_readonly; } + map->pages_vm_start = vma->vm_start; + if (use_ptemod) { - map->vma = vma; err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); - if (err) { - map->vma = NULL; + if (err) goto out_unlock_put; - } + + map->notifier_init = true; } mutex_unlock(&priv->lock); @@ -1099,7 +1097,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) */ mmu_interval_read_begin(&map->notifier); - map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); @@ -1128,13 +1125,8 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) out_unlock_put: mutex_unlock(&priv->lock); out_put_map: - if (use_ptemod) { + if (use_ptemod) unmap_grant_pages(map, 0, map->count); - if (map->vma) { - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } - } gntdev_put_map(priv, map); return err; }

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] xen/gntdev: Accommodate VMA splitting" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 5c13a4a0291b ("xen/gntdev: Accommodate VMA splitting") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") 30dcc56bba91 ("xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests") 970655aa9b42 ("xen/gntdev: fix gntdev_mmap() error exit path") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") 9293724192a7 ("xen/gntdev: Do not use mm notifiers with autotranslating guests") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") ee7f5225dc3c ("xen: Stop abusing DT of_dma_configure API") bce5963bcb4f ("xen/events: fix binding user event channels to cpus") 8b1e0f81fb6f ("mm/pgtable: drop pgtable_t variable from pte_fn_t functions") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:06 -0400 Subject: [PATCH] xen/gntdev: Accommodate VMA splitting Prior to this commit, the gntdev driver code did not handle the following scenario correctly with paravirtualized (PV) Xen domains: * User process sets up a gntdev mapping composed of two grant mappings (i.e., two pages shared by another Xen domain). * User process munmap()s one of the pages. * User process munmap()s the remaining page. * User process exits. In the scenario above, the user process would cause the kernel to log the following messages in dmesg for the first munmap(), and the second munmap() call would result in similar log messages: BUG: Bad page map in process doublemap.test pte:... pmd:... page:0000000057c97bff refcount:1 mapcount:-1 \ mapping:0000000000000000 index:0x0 pfn:... ... page dumped because: bad pte ... file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0 ... Call Trace: <TASK> dump_stack_lvl+0x46/0x5e print_bad_pte.cold+0x66/0xb6 unmap_page_range+0x7e5/0xdc0 unmap_vmas+0x78/0xf0 unmap_region+0xa8/0x110 __do_munmap+0x1ea/0x4e0 __vm_munmap+0x75/0x120 __x64_sys_munmap+0x28/0x40 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x61/0xcb ... For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG) would print out the following and trigger a general protection fault in the affected Xen PV domain: (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... As of this writing, gntdev_grant_map structure's vma field (referred to as map->vma below) is mainly used for checking the start and end addresses of mappings. However, with split VMAs, these may change, and there could be more than one VMA associated with a gntdev mapping. Hence, remove the use of map->vma and rely on map->pages_vm_start for the original start address and on (map->count << PAGE_SHIFT) for the original mapping size. Let the invalidate() and find_special_page() hooks use these. Also, given that there can be multiple VMAs associated with a gntdev mapping, move the "mmu_interval_notifier_remove(&map->notifier)" call to the end of gntdev_put_map, so that the MMU notifier is only removed after the closing of the last remaining VMA. Finally, use an atomic to prevent inadvertent gntdev mapping re-use, instead of using the map->live_grants atomic counter and/or the map->vma pointer (the latter of which is now removed). This prevents the userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the same address range as a previously set up gntdev mapping. This scenario can be summarized with the following call-trace, which was valid prior to this commit: mmap gntdev_mmap mmap (repeat mmap with MAP_FIXED over the same address range) gntdev_invalidate unmap_grant_pages (sets 'being_removed' entries to true) gnttab_unmap_refs_async unmap_single_vma gntdev_mmap (maps the shared pages again) munmap gntdev_invalidate unmap_grant_pages (no-op because 'being_removed' entries are true) unmap_single_vma (For PV domains, Xen reports that a granted page is being unmapped and triggers a general protection fault in the affected domain, if Xen was built with CONFIG_DEBUG) The fix for this last scenario could be worth its own commit, but we opted for a single commit, because removing the gntdev_grant_map structure's vma field requires guarding the entry to gntdev_mmap(), and the live_grants atomic counter is not sufficient on its own to prevent the mmap() over a pre-existing mapping. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h index 40ef379c28ab..9c286b2a1900 100644 --- a/drivers/xen/gntdev-common.h +++ b/drivers/xen/gntdev-common.h @@ -44,9 +44,10 @@ struct gntdev_unmap_notify { }; struct gntdev_grant_map { + atomic_t in_use; struct mmu_interval_notifier notifier; + bool notifier_init; struct list_head next; - struct vm_area_struct *vma; int index; int count; int flags; diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index eb0586b9767d..4d9a3050de6a 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -286,6 +286,9 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) */ } + if (use_ptemod && map->notifier_init) + mmu_interval_notifier_remove(&map->notifier); + if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); @@ -298,7 +301,7 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) { struct gntdev_grant_map *map = data; - unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; + unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | (1 << _GNTMAP_guest_avail0); u64 pte_maddr; @@ -508,11 +511,7 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); - if (use_ptemod) { - WARN_ON(map->vma != vma); - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } + vma->vm_private_data = NULL; gntdev_put_map(priv, map); } @@ -540,29 +539,30 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn, struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; + unsigned long map_start, map_end; if (!mmu_notifier_range_blockable(range)) return false; + map_start = map->pages_vm_start; + map_end = map->pages_vm_start + (map->count << PAGE_SHIFT); + /* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ - if (map->vma->vm_start >= range->end || - map->vma->vm_end <= range->start) + if (map_start >= range->end || map_end <= range->start) return true; - mstart = max(range->start, map->vma->vm_start); - mend = min(range->end, map->vma->vm_end); + mstart = max(range->start, map_start); + mend = min(range->end, map_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", - map->index, map->count, - map->vma->vm_start, map->vma->vm_end, - range->start, range->end, mstart, mend); - unmap_grant_pages(map, - (mstart - map->vma->vm_start) >> PAGE_SHIFT, - (mend - mstart) >> PAGE_SHIFT); + map->index, map->count, map_start, map_end, + range->start, range->end, mstart, mend); + unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, + (mend - mstart) >> PAGE_SHIFT); return true; } @@ -1042,18 +1042,15 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) return -EINVAL; pr_debug("map %d+%d at %lx (pgoff %lx)\n", - index, count, vma->vm_start, vma->vm_pgoff); + index, count, vma->vm_start, vma->vm_pgoff); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; - if (use_ptemod && map->vma) - goto unlock_out; - if (atomic_read(&map->live_grants)) { - err = -EAGAIN; + if (!atomic_add_unless(&map->in_use, 1, 1)) goto unlock_out; - } + refcount_inc(&map->users); vma->vm_ops = &gntdev_vmops; @@ -1074,15 +1071,16 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) map->flags |= GNTMAP_readonly; } + map->pages_vm_start = vma->vm_start; + if (use_ptemod) { - map->vma = vma; err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); - if (err) { - map->vma = NULL; + if (err) goto out_unlock_put; - } + + map->notifier_init = true; } mutex_unlock(&priv->lock); @@ -1099,7 +1097,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) */ mmu_interval_read_begin(&map->notifier); - map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); @@ -1128,13 +1125,8 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) out_unlock_put: mutex_unlock(&priv->lock); out_put_map: - if (use_ptemod) { + if (use_ptemod) unmap_grant_pages(map, 0, map->count); - if (map->vma) { - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } - } gntdev_put_map(priv, map); return err; }

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] xen/gntdev: Accommodate VMA splitting" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 5c13a4a0291b ("xen/gntdev: Accommodate VMA splitting") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") 30dcc56bba91 ("xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests") 970655aa9b42 ("xen/gntdev: fix gntdev_mmap() error exit path") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") 9293724192a7 ("xen/gntdev: Do not use mm notifiers with autotranslating guests") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:06 -0400 Subject: [PATCH] xen/gntdev: Accommodate VMA splitting Prior to this commit, the gntdev driver code did not handle the following scenario correctly with paravirtualized (PV) Xen domains: * User process sets up a gntdev mapping composed of two grant mappings (i.e., two pages shared by another Xen domain). * User process munmap()s one of the pages. * User process munmap()s the remaining page. * User process exits. In the scenario above, the user process would cause the kernel to log the following messages in dmesg for the first munmap(), and the second munmap() call would result in similar log messages: BUG: Bad page map in process doublemap.test pte:... pmd:... page:0000000057c97bff refcount:1 mapcount:-1 \ mapping:0000000000000000 index:0x0 pfn:... ... page dumped because: bad pte ... file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0 ... Call Trace: <TASK> dump_stack_lvl+0x46/0x5e print_bad_pte.cold+0x66/0xb6 unmap_page_range+0x7e5/0xdc0 unmap_vmas+0x78/0xf0 unmap_region+0xa8/0x110 __do_munmap+0x1ea/0x4e0 __vm_munmap+0x75/0x120 __x64_sys_munmap+0x28/0x40 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x61/0xcb ... For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG) would print out the following and trigger a general protection fault in the affected Xen PV domain: (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... As of this writing, gntdev_grant_map structure's vma field (referred to as map->vma below) is mainly used for checking the start and end addresses of mappings. However, with split VMAs, these may change, and there could be more than one VMA associated with a gntdev mapping. Hence, remove the use of map->vma and rely on map->pages_vm_start for the original start address and on (map->count << PAGE_SHIFT) for the original mapping size. Let the invalidate() and find_special_page() hooks use these. Also, given that there can be multiple VMAs associated with a gntdev mapping, move the "mmu_interval_notifier_remove(&map->notifier)" call to the end of gntdev_put_map, so that the MMU notifier is only removed after the closing of the last remaining VMA. Finally, use an atomic to prevent inadvertent gntdev mapping re-use, instead of using the map->live_grants atomic counter and/or the map->vma pointer (the latter of which is now removed). This prevents the userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the same address range as a previously set up gntdev mapping. This scenario can be summarized with the following call-trace, which was valid prior to this commit: mmap gntdev_mmap mmap (repeat mmap with MAP_FIXED over the same address range) gntdev_invalidate unmap_grant_pages (sets 'being_removed' entries to true) gnttab_unmap_refs_async unmap_single_vma gntdev_mmap (maps the shared pages again) munmap gntdev_invalidate unmap_grant_pages (no-op because 'being_removed' entries are true) unmap_single_vma (For PV domains, Xen reports that a granted page is being unmapped and triggers a general protection fault in the affected domain, if Xen was built with CONFIG_DEBUG) The fix for this last scenario could be worth its own commit, but we opted for a single commit, because removing the gntdev_grant_map structure's vma field requires guarding the entry to gntdev_mmap(), and the live_grants atomic counter is not sufficient on its own to prevent the mmap() over a pre-existing mapping. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h index 40ef379c28ab..9c286b2a1900 100644 --- a/drivers/xen/gntdev-common.h +++ b/drivers/xen/gntdev-common.h @@ -44,9 +44,10 @@ struct gntdev_unmap_notify { }; struct gntdev_grant_map { + atomic_t in_use; struct mmu_interval_notifier notifier; + bool notifier_init; struct list_head next; - struct vm_area_struct *vma; int index; int count; int flags; diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index eb0586b9767d..4d9a3050de6a 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -286,6 +286,9 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) */ } + if (use_ptemod && map->notifier_init) + mmu_interval_notifier_remove(&map->notifier); + if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); @@ -298,7 +301,7 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) { struct gntdev_grant_map *map = data; - unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; + unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | (1 << _GNTMAP_guest_avail0); u64 pte_maddr; @@ -508,11 +511,7 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); - if (use_ptemod) { - WARN_ON(map->vma != vma); - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } + vma->vm_private_data = NULL; gntdev_put_map(priv, map); } @@ -540,29 +539,30 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn, struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; + unsigned long map_start, map_end; if (!mmu_notifier_range_blockable(range)) return false; + map_start = map->pages_vm_start; + map_end = map->pages_vm_start + (map->count << PAGE_SHIFT); + /* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ - if (map->vma->vm_start >= range->end || - map->vma->vm_end <= range->start) + if (map_start >= range->end || map_end <= range->start) return true; - mstart = max(range->start, map->vma->vm_start); - mend = min(range->end, map->vma->vm_end); + mstart = max(range->start, map_start); + mend = min(range->end, map_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", - map->index, map->count, - map->vma->vm_start, map->vma->vm_end, - range->start, range->end, mstart, mend); - unmap_grant_pages(map, - (mstart - map->vma->vm_start) >> PAGE_SHIFT, - (mend - mstart) >> PAGE_SHIFT); + map->index, map->count, map_start, map_end, + range->start, range->end, mstart, mend); + unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, + (mend - mstart) >> PAGE_SHIFT); return true; } @@ -1042,18 +1042,15 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) return -EINVAL; pr_debug("map %d+%d at %lx (pgoff %lx)\n", - index, count, vma->vm_start, vma->vm_pgoff); + index, count, vma->vm_start, vma->vm_pgoff); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; - if (use_ptemod && map->vma) - goto unlock_out; - if (atomic_read(&map->live_grants)) { - err = -EAGAIN; + if (!atomic_add_unless(&map->in_use, 1, 1)) goto unlock_out; - } + refcount_inc(&map->users); vma->vm_ops = &gntdev_vmops; @@ -1074,15 +1071,16 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) map->flags |= GNTMAP_readonly; } + map->pages_vm_start = vma->vm_start; + if (use_ptemod) { - map->vma = vma; err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); - if (err) { - map->vma = NULL; + if (err) goto out_unlock_put; - } + + map->notifier_init = true; } mutex_unlock(&priv->lock); @@ -1099,7 +1097,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) */ mmu_interval_read_begin(&map->notifier); - map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); @@ -1128,13 +1125,8 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) out_unlock_put: mutex_unlock(&priv->lock); out_put_map: - if (use_ptemod) { + if (use_ptemod) unmap_grant_pages(map, 0, map->count); - if (map->vma) { - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } - } gntdev_put_map(priv, map); return err; }

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] xen/gntdev: Accommodate VMA splitting" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 5c13a4a0291b ("xen/gntdev: Accommodate VMA splitting") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") 30dcc56bba91 ("xen: assume XENFEAT_gnttab_map_avail_bits being set for pv guests") 970655aa9b42 ("xen/gntdev: fix gntdev_mmap() error exit path") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:06 -0400 Subject: [PATCH] xen/gntdev: Accommodate VMA splitting Prior to this commit, the gntdev driver code did not handle the following scenario correctly with paravirtualized (PV) Xen domains: * User process sets up a gntdev mapping composed of two grant mappings (i.e., two pages shared by another Xen domain). * User process munmap()s one of the pages. * User process munmap()s the remaining page. * User process exits. In the scenario above, the user process would cause the kernel to log the following messages in dmesg for the first munmap(), and the second munmap() call would result in similar log messages: BUG: Bad page map in process doublemap.test pte:... pmd:... page:0000000057c97bff refcount:1 mapcount:-1 \ mapping:0000000000000000 index:0x0 pfn:... ... page dumped because: bad pte ... file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0 ... Call Trace: <TASK> dump_stack_lvl+0x46/0x5e print_bad_pte.cold+0x66/0xb6 unmap_page_range+0x7e5/0xdc0 unmap_vmas+0x78/0xf0 unmap_region+0xa8/0x110 __do_munmap+0x1ea/0x4e0 __vm_munmap+0x75/0x120 __x64_sys_munmap+0x28/0x40 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x61/0xcb ... For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG) would print out the following and trigger a general protection fault in the affected Xen PV domain: (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ... As of this writing, gntdev_grant_map structure's vma field (referred to as map->vma below) is mainly used for checking the start and end addresses of mappings. However, with split VMAs, these may change, and there could be more than one VMA associated with a gntdev mapping. Hence, remove the use of map->vma and rely on map->pages_vm_start for the original start address and on (map->count << PAGE_SHIFT) for the original mapping size. Let the invalidate() and find_special_page() hooks use these. Also, given that there can be multiple VMAs associated with a gntdev mapping, move the "mmu_interval_notifier_remove(&map->notifier)" call to the end of gntdev_put_map, so that the MMU notifier is only removed after the closing of the last remaining VMA. Finally, use an atomic to prevent inadvertent gntdev mapping re-use, instead of using the map->live_grants atomic counter and/or the map->vma pointer (the latter of which is now removed). This prevents the userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the same address range as a previously set up gntdev mapping. This scenario can be summarized with the following call-trace, which was valid prior to this commit: mmap gntdev_mmap mmap (repeat mmap with MAP_FIXED over the same address range) gntdev_invalidate unmap_grant_pages (sets 'being_removed' entries to true) gnttab_unmap_refs_async unmap_single_vma gntdev_mmap (maps the shared pages again) munmap gntdev_invalidate unmap_grant_pages (no-op because 'being_removed' entries are true) unmap_single_vma (For PV domains, Xen reports that a granted page is being unmapped and triggers a general protection fault in the affected domain, if Xen was built with CONFIG_DEBUG) The fix for this last scenario could be worth its own commit, but we opted for a single commit, because removing the gntdev_grant_map structure's vma field requires guarding the entry to gntdev_mmap(), and the live_grants atomic counter is not sufficient on its own to prevent the mmap() over a pre-existing mapping. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h index 40ef379c28ab..9c286b2a1900 100644 --- a/drivers/xen/gntdev-common.h +++ b/drivers/xen/gntdev-common.h @@ -44,9 +44,10 @@ struct gntdev_unmap_notify { }; struct gntdev_grant_map { + atomic_t in_use; struct mmu_interval_notifier notifier; + bool notifier_init; struct list_head next; - struct vm_area_struct *vma; int index; int count; int flags; diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index eb0586b9767d..4d9a3050de6a 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -286,6 +286,9 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) */ } + if (use_ptemod && map->notifier_init) + mmu_interval_notifier_remove(&map->notifier); + if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); @@ -298,7 +301,7 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) { struct gntdev_grant_map *map = data; - unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; + unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | (1 << _GNTMAP_guest_avail0); u64 pte_maddr; @@ -508,11 +511,7 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); - if (use_ptemod) { - WARN_ON(map->vma != vma); - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } + vma->vm_private_data = NULL; gntdev_put_map(priv, map); } @@ -540,29 +539,30 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn, struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; + unsigned long map_start, map_end; if (!mmu_notifier_range_blockable(range)) return false; + map_start = map->pages_vm_start; + map_end = map->pages_vm_start + (map->count << PAGE_SHIFT); + /* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ - if (map->vma->vm_start >= range->end || - map->vma->vm_end <= range->start) + if (map_start >= range->end || map_end <= range->start) return true; - mstart = max(range->start, map->vma->vm_start); - mend = min(range->end, map->vma->vm_end); + mstart = max(range->start, map_start); + mend = min(range->end, map_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", - map->index, map->count, - map->vma->vm_start, map->vma->vm_end, - range->start, range->end, mstart, mend); - unmap_grant_pages(map, - (mstart - map->vma->vm_start) >> PAGE_SHIFT, - (mend - mstart) >> PAGE_SHIFT); + map->index, map->count, map_start, map_end, + range->start, range->end, mstart, mend); + unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, + (mend - mstart) >> PAGE_SHIFT); return true; } @@ -1042,18 +1042,15 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) return -EINVAL; pr_debug("map %d+%d at %lx (pgoff %lx)\n", - index, count, vma->vm_start, vma->vm_pgoff); + index, count, vma->vm_start, vma->vm_pgoff); mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; - if (use_ptemod && map->vma) - goto unlock_out; - if (atomic_read(&map->live_grants)) { - err = -EAGAIN; + if (!atomic_add_unless(&map->in_use, 1, 1)) goto unlock_out; - } + refcount_inc(&map->users); vma->vm_ops = &gntdev_vmops; @@ -1074,15 +1071,16 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) map->flags |= GNTMAP_readonly; } + map->pages_vm_start = vma->vm_start; + if (use_ptemod) { - map->vma = vma; err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); - if (err) { - map->vma = NULL; + if (err) goto out_unlock_put; - } + + map->notifier_init = true; } mutex_unlock(&priv->lock); @@ -1099,7 +1097,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) */ mmu_interval_read_begin(&map->notifier); - map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); @@ -1128,13 +1125,8 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) out_unlock_put: mutex_unlock(&priv->lock); out_put_map: - if (use_ptemod) { + if (use_ptemod) unmap_grant_pages(map, 0, map->count); - if (map->vma) { - mmu_interval_notifier_remove(&map->notifier); - map->vma = NULL; - } - } gntdev_put_map(priv, map); return err; }

2 years, 2 months

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FAILED: patch "[PATCH] xen/gntdev: Prevent leaking grants" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 0991028cd495 ("xen/gntdev: Prevent leaking grants") 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") ee7f5225dc3c ("xen: Stop abusing DT of_dma_configure API") bce5963bcb4f ("xen/events: fix binding user event channels to cpus") dfcd66604c1c ("mm/mmu_notifier: convert user range->blockable to helper function") a3e0d41c2b1f ("mm/hmm: improve driver API to work and wait over a range") 73231612dc7c ("mm/hmm: improve and rename hmm_vma_fault() to hmm_range_fault()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 0991028cd49567d7016d1b224fe0117c35059f86 Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:05 -0400 Subject: [PATCH] xen/gntdev: Prevent leaking grants Prior to this commit, if a grant mapping operation failed partially, some of the entries in the map_ops array would be invalid, whereas all of the entries in the kmap_ops array would be valid. This in turn would cause the following logic in gntdev_map_grant_pages to become invalid: for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; if (!use_ptemod) alloced++; } if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) { if (map->map_ops[i].status == GNTST_okay) alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } } } ... atomic_add(alloced, &map->live_grants); Assume that use_ptemod is true (i.e., the domain mapping the granted pages is a paravirtualized domain). In the code excerpt above, note that the "alloced" variable is only incremented when both kmap_ops[i].status and map_ops[i].status are set to GNTST_okay (i.e., both mapping operations are successful). However, as also noted above, there are cases where a grant mapping operation fails partially, breaking the assumption of the code excerpt above. The aforementioned causes map->live_grants to be incorrectly set. In some cases, all of the map_ops mappings fail, but all of the kmap_ops mappings succeed, meaning that live_grants may remain zero. This in turn makes it impossible to unmap the successfully grant-mapped pages pointed to by kmap_ops, because unmap_grant_pages has the following snippet of code at its beginning: if (atomic_read(&map->live_grants) == 0) return; /* Nothing to do */ In other cases where only some of the map_ops mappings fail but all kmap_ops mappings succeed, live_grants is made positive, but when the user requests unmapping the grant-mapped pages, __unmap_grant_pages_done will then make map->live_grants negative, because the latter function does not check if all of the pages that were requested to be unmapped were actually unmapped, and the same function unconditionally subtracts "data->count" (i.e., a value that can be greater than map->live_grants) from map->live_grants. The side effects of a negative live_grants value have not been studied. The net effect of all of this is that grant references are leaked in one of the above conditions. In Qubes OS v4.1 (which uses Xen's grant mechanism extensively for X11 GUI isolation), this issue manifests itself with warning messages like the following to be printed out by the Linux kernel in the VM that had granted pages (that contain X11 GUI window data) to dom0: "g.e. 0x1234 still pending", especially after the user rapidly resizes GUI VM windows (causing some grant-mapping operations to partially or completely fail, due to the fact that the VM unshares some of the pages as part of the window resizing, making the pages impossible to grant-map from dom0). The fix for this issue involves counting all successful map_ops and kmap_ops mappings separately, and then adding the sum to live_grants. During unmapping, only the number of successfully unmapped grants is subtracted from live_grants. The code is also modified to check for negative live_grants values after the subtraction and warn the user. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Acked-by: Demi Marie Obenour <demi(a)invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 84b143eef395..eb0586b9767d 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -367,8 +367,7 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; - if (!use_ptemod) - alloced++; + alloced++; } else if (!err) err = -EINVAL; @@ -377,8 +376,7 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) { - if (map->map_ops[i].status == GNTST_okay) - alloced++; + alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } else if (!err) err = -EINVAL; @@ -394,8 +392,14 @@ static void __unmap_grant_pages_done(int result, unsigned int i; struct gntdev_grant_map *map = data->data; unsigned int offset = data->unmap_ops - map->unmap_ops; + int successful_unmaps = 0; + int live_grants; for (i = 0; i < data->count; i++) { + if (map->unmap_ops[offset + i].status == GNTST_okay && + map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) + successful_unmaps++; + WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay && map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("unmap handle=%d st=%d\n", @@ -403,6 +407,10 @@ static void __unmap_grant_pages_done(int result, map->unmap_ops[offset+i].status); map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; if (use_ptemod) { + if (map->kunmap_ops[offset + i].status == GNTST_okay && + map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) + successful_unmaps++; + WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay && map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("kunmap handle=%u st=%d\n", @@ -411,11 +419,15 @@ static void __unmap_grant_pages_done(int result, map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; } } + /* * Decrease the live-grant counter. This must happen after the loop to * prevent premature reuse of the grants by gnttab_mmap(). */ - atomic_sub(data->count, &map->live_grants); + live_grants = atomic_sub_return(successful_unmaps, &map->live_grants); + if (WARN_ON(live_grants < 0)) + pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n", + __func__, live_grants, successful_unmaps); /* Release reference taken by __unmap_grant_pages */ gntdev_put_map(NULL, map);

2 years, 2 months

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FAILED: patch "[PATCH] xen/gntdev: Prevent leaking grants" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 0991028cd495 ("xen/gntdev: Prevent leaking grants") 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") ee7f5225dc3c ("xen: Stop abusing DT of_dma_configure API") bce5963bcb4f ("xen/events: fix binding user event channels to cpus") dfcd66604c1c ("mm/mmu_notifier: convert user range->blockable to helper function") a3e0d41c2b1f ("mm/hmm: improve driver API to work and wait over a range") 73231612dc7c ("mm/hmm: improve and rename hmm_vma_fault() to hmm_range_fault()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 0991028cd49567d7016d1b224fe0117c35059f86 Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:05 -0400 Subject: [PATCH] xen/gntdev: Prevent leaking grants Prior to this commit, if a grant mapping operation failed partially, some of the entries in the map_ops array would be invalid, whereas all of the entries in the kmap_ops array would be valid. This in turn would cause the following logic in gntdev_map_grant_pages to become invalid: for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; if (!use_ptemod) alloced++; } if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) { if (map->map_ops[i].status == GNTST_okay) alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } } } ... atomic_add(alloced, &map->live_grants); Assume that use_ptemod is true (i.e., the domain mapping the granted pages is a paravirtualized domain). In the code excerpt above, note that the "alloced" variable is only incremented when both kmap_ops[i].status and map_ops[i].status are set to GNTST_okay (i.e., both mapping operations are successful). However, as also noted above, there are cases where a grant mapping operation fails partially, breaking the assumption of the code excerpt above. The aforementioned causes map->live_grants to be incorrectly set. In some cases, all of the map_ops mappings fail, but all of the kmap_ops mappings succeed, meaning that live_grants may remain zero. This in turn makes it impossible to unmap the successfully grant-mapped pages pointed to by kmap_ops, because unmap_grant_pages has the following snippet of code at its beginning: if (atomic_read(&map->live_grants) == 0) return; /* Nothing to do */ In other cases where only some of the map_ops mappings fail but all kmap_ops mappings succeed, live_grants is made positive, but when the user requests unmapping the grant-mapped pages, __unmap_grant_pages_done will then make map->live_grants negative, because the latter function does not check if all of the pages that were requested to be unmapped were actually unmapped, and the same function unconditionally subtracts "data->count" (i.e., a value that can be greater than map->live_grants) from map->live_grants. The side effects of a negative live_grants value have not been studied. The net effect of all of this is that grant references are leaked in one of the above conditions. In Qubes OS v4.1 (which uses Xen's grant mechanism extensively for X11 GUI isolation), this issue manifests itself with warning messages like the following to be printed out by the Linux kernel in the VM that had granted pages (that contain X11 GUI window data) to dom0: "g.e. 0x1234 still pending", especially after the user rapidly resizes GUI VM windows (causing some grant-mapping operations to partially or completely fail, due to the fact that the VM unshares some of the pages as part of the window resizing, making the pages impossible to grant-map from dom0). The fix for this issue involves counting all successful map_ops and kmap_ops mappings separately, and then adding the sum to live_grants. During unmapping, only the number of successfully unmapped grants is subtracted from live_grants. The code is also modified to check for negative live_grants values after the subtraction and warn the user. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Acked-by: Demi Marie Obenour <demi(a)invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 84b143eef395..eb0586b9767d 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -367,8 +367,7 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; - if (!use_ptemod) - alloced++; + alloced++; } else if (!err) err = -EINVAL; @@ -377,8 +376,7 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) { - if (map->map_ops[i].status == GNTST_okay) - alloced++; + alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } else if (!err) err = -EINVAL; @@ -394,8 +392,14 @@ static void __unmap_grant_pages_done(int result, unsigned int i; struct gntdev_grant_map *map = data->data; unsigned int offset = data->unmap_ops - map->unmap_ops; + int successful_unmaps = 0; + int live_grants; for (i = 0; i < data->count; i++) { + if (map->unmap_ops[offset + i].status == GNTST_okay && + map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) + successful_unmaps++; + WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay && map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("unmap handle=%d st=%d\n", @@ -403,6 +407,10 @@ static void __unmap_grant_pages_done(int result, map->unmap_ops[offset+i].status); map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; if (use_ptemod) { + if (map->kunmap_ops[offset + i].status == GNTST_okay && + map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) + successful_unmaps++; + WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay && map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("kunmap handle=%u st=%d\n", @@ -411,11 +419,15 @@ static void __unmap_grant_pages_done(int result, map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; } } + /* * Decrease the live-grant counter. This must happen after the loop to * prevent premature reuse of the grants by gnttab_mmap(). */ - atomic_sub(data->count, &map->live_grants); + live_grants = atomic_sub_return(successful_unmaps, &map->live_grants); + if (WARN_ON(live_grants < 0)) + pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n", + __func__, live_grants, successful_unmaps); /* Release reference taken by __unmap_grant_pages */ gntdev_put_map(NULL, map);

2 years, 2 months

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FAILED: patch "[PATCH] xen/gntdev: Prevent leaking grants" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 0991028cd495 ("xen/gntdev: Prevent leaking grants") 166d38632316 ("xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE") dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") ce2f46f3531a ("xen/gntdev: fix unmap notification order") f28347cc6639 ("Xen/gntdev: don't ignore kernel unmapping error") bce21a2b48ed ("Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}") 36caa3fedf06 ("Xen/gntdev: don't needlessly allocate k{,un}map_ops[]") 8310b77b48c5 ("Xen/gnttab: handle p2m update errors on a per-slot basis") 36bf1dfb8b26 ("xen/arm: don't ignore return errors from set_phys_to_machine") ebee0eab0859 ("Xen/gntdev: correct error checking in gntdev_map_grant_pages()") dbe5283605b3 ("Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()") 0102e4efda76 ("xen: Use evtchn_type_t as a type for event channels") b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()") 3b06ac6707c1 ("xen/gntdev: replace global limit of mapped pages by limit per call") d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") ee7f5225dc3c ("xen: Stop abusing DT of_dma_configure API") bce5963bcb4f ("xen/events: fix binding user event channels to cpus") dfcd66604c1c ("mm/mmu_notifier: convert user range->blockable to helper function") a3e0d41c2b1f ("mm/hmm: improve driver API to work and wait over a range") 73231612dc7c ("mm/hmm: improve and rename hmm_vma_fault() to hmm_range_fault()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 0991028cd49567d7016d1b224fe0117c35059f86 Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" <m.v.b(a)runbox.com> Date: Sun, 2 Oct 2022 18:20:05 -0400 Subject: [PATCH] xen/gntdev: Prevent leaking grants Prior to this commit, if a grant mapping operation failed partially, some of the entries in the map_ops array would be invalid, whereas all of the entries in the kmap_ops array would be valid. This in turn would cause the following logic in gntdev_map_grant_pages to become invalid: for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; if (!use_ptemod) alloced++; } if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) { if (map->map_ops[i].status == GNTST_okay) alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } } } ... atomic_add(alloced, &map->live_grants); Assume that use_ptemod is true (i.e., the domain mapping the granted pages is a paravirtualized domain). In the code excerpt above, note that the "alloced" variable is only incremented when both kmap_ops[i].status and map_ops[i].status are set to GNTST_okay (i.e., both mapping operations are successful). However, as also noted above, there are cases where a grant mapping operation fails partially, breaking the assumption of the code excerpt above. The aforementioned causes map->live_grants to be incorrectly set. In some cases, all of the map_ops mappings fail, but all of the kmap_ops mappings succeed, meaning that live_grants may remain zero. This in turn makes it impossible to unmap the successfully grant-mapped pages pointed to by kmap_ops, because unmap_grant_pages has the following snippet of code at its beginning: if (atomic_read(&map->live_grants) == 0) return; /* Nothing to do */ In other cases where only some of the map_ops mappings fail but all kmap_ops mappings succeed, live_grants is made positive, but when the user requests unmapping the grant-mapped pages, __unmap_grant_pages_done will then make map->live_grants negative, because the latter function does not check if all of the pages that were requested to be unmapped were actually unmapped, and the same function unconditionally subtracts "data->count" (i.e., a value that can be greater than map->live_grants) from map->live_grants. The side effects of a negative live_grants value have not been studied. The net effect of all of this is that grant references are leaked in one of the above conditions. In Qubes OS v4.1 (which uses Xen's grant mechanism extensively for X11 GUI isolation), this issue manifests itself with warning messages like the following to be printed out by the Linux kernel in the VM that had granted pages (that contain X11 GUI window data) to dom0: "g.e. 0x1234 still pending", especially after the user rapidly resizes GUI VM windows (causing some grant-mapping operations to partially or completely fail, due to the fact that the VM unshares some of the pages as part of the window resizing, making the pages impossible to grant-map from dom0). The fix for this issue involves counting all successful map_ops and kmap_ops mappings separately, and then adding the sum to live_grants. During unmapping, only the number of successfully unmapped grants is subtracted from live_grants. The code is also modified to check for negative live_grants values after the subtraction and warn the user. Link: https://github.com/QubesOS/qubes-issues/issues/7631 Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()") Cc: stable(a)vger.kernel.org Signed-off-by: M. Vefa Bicakci <m.v.b(a)runbox.com> Acked-by: Demi Marie Obenour <demi(a)invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com Signed-off-by: Juergen Gross <jgross(a)suse.com> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 84b143eef395..eb0586b9767d 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -367,8 +367,7 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; - if (!use_ptemod) - alloced++; + alloced++; } else if (!err) err = -EINVAL; @@ -377,8 +376,7 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map) if (use_ptemod) { if (map->kmap_ops[i].status == GNTST_okay) { - if (map->map_ops[i].status == GNTST_okay) - alloced++; + alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } else if (!err) err = -EINVAL; @@ -394,8 +392,14 @@ static void __unmap_grant_pages_done(int result, unsigned int i; struct gntdev_grant_map *map = data->data; unsigned int offset = data->unmap_ops - map->unmap_ops; + int successful_unmaps = 0; + int live_grants; for (i = 0; i < data->count; i++) { + if (map->unmap_ops[offset + i].status == GNTST_okay && + map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) + successful_unmaps++; + WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay && map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("unmap handle=%d st=%d\n", @@ -403,6 +407,10 @@ static void __unmap_grant_pages_done(int result, map->unmap_ops[offset+i].status); map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; if (use_ptemod) { + if (map->kunmap_ops[offset + i].status == GNTST_okay && + map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) + successful_unmaps++; + WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay && map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("kunmap handle=%u st=%d\n", @@ -411,11 +419,15 @@ static void __unmap_grant_pages_done(int result, map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; } } + /* * Decrease the live-grant counter. This must happen after the loop to * prevent premature reuse of the grants by gnttab_mmap(). */ - atomic_sub(data->count, &map->live_grants); + live_grants = atomic_sub_return(successful_unmaps, &map->live_grants); + if (WARN_ON(live_grants < 0)) + pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n", + __func__, live_grants, successful_unmaps); /* Release reference taken by __unmap_grant_pages */ gntdev_put_map(NULL, map);

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Linux-stable-mirror October 2022