November 2024 - Linux-stable-mirror

[PATCH] drm/dp_mst: Fix MST sideband message body length check

by Imre Deak

Fix the MST sideband message body length check, which must be at least 1 byte accounting for the message body CRC (aka message data CRC) at the end of the message. This fixes a case where an MST branch device returns a header with a correct header CRC (indicating a correctly received body length), with the body length being incorrectly set to 0. This will later lead to a memory corruption in drm_dp_sideband_append_payload() and the following errors in dmesg: UBSAN: array-index-out-of-bounds in drivers/gpu/drm/display/drm_dp_mst_topology.c:786:25 index -1 is out of range for type 'u8 [48]' Call Trace: drm_dp_sideband_append_payload+0x33d/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] memcpy: detected field-spanning write (size 18446744073709551615) of single field "&msg->msg[msg->curlen]" at drivers/gpu/drm/display/drm_dp_mst_topology.c:791 (size 256) Call Trace: drm_dp_sideband_append_payload+0x324/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] Cc: <stable(a)vger.kernel.org> Cc: Lyude Paul <lyude(a)redhat.com> Signed-off-by: Imre Deak <imre.deak(a)intel.com> --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index ac90118b9e7a8..e6ee180815b20 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -320,6 +320,9 @@ static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr hdr->broadcast = (buf[idx] >> 7) & 0x1; hdr->path_msg = (buf[idx] >> 6) & 0x1; hdr->msg_len = buf[idx] & 0x3f; + if (hdr->msg_len < 1) /* min space for body CRC */ + return false; + idx++; hdr->somt = (buf[idx] >> 7) & 0x1; hdr->eomt = (buf[idx] >> 6) & 0x1; -- 2.44.2

6 months, 2 weeks

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[PATCH 1/2] mm: Open-code PageTail in folio_flags() and const_folio_flags()

by Matthew Wilcox (Oracle)

It is unsafe to call PageTail() in dump_page() as page_is_fake_head() will almost certainly return true when called on a head page that is copied to the stack. That will cause the VM_BUG_ON_PGFLAGS() in const_folio_flags() to trigger when it shouldn't. Fortunately, we don't need to call PageTail() here; it's fine to have a pointer to a virtual alias of the page's flag word rather than the real page's flag word. Fixes: fae7d834c43c (mm: add __dump_folio()) Signed-off-by: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: stable(a)vger.kernel.org --- include/linux/page-flags.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 2220bfec278e..cf46ac720802 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -306,7 +306,7 @@ static const unsigned long *const_folio_flags(const struct folio *folio, { const struct page *page = &folio->page; - VM_BUG_ON_PGFLAGS(PageTail(page), page); + VM_BUG_ON_PGFLAGS(page->compound_head & 1, page); VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); return &page[n].flags; } @@ -315,7 +315,7 @@ static unsigned long *folio_flags(struct folio *folio, unsigned n) { struct page *page = &folio->page; - VM_BUG_ON_PGFLAGS(PageTail(page), page); + VM_BUG_ON_PGFLAGS(page->compound_head & 1, page); VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page); return &page[n].flags; } -- 2.45.2

6 months, 2 weeks

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[PATCH v4 0/7] media: uvcvideo: Implement the Privacy GPIO as a evdev

by Ricardo Ribalda

Some notebooks have a button to disable the camera (not to be mistaken with the mechanical cover). This is a standard GPIO linked to the camera via the ACPI table. 4 years ago we added support for this button in UVC via the Privacy control. This has three issues: - If the camera has its own privacy control, it will be masked. - We need to power-up the camera to read the privacy control gpio. - Other drivers have not followed this approach and have used evdev. We tried to fix the power-up issues implementing "granular power saving" but it has been more complicated than anticipated... This patchset implements the Privacy GPIO as a evdev. The first patch of this set is already in Laurent's tree... but I include it to get some CI coverage. Signed-off-by: Ricardo Ribalda <ribalda(a)chromium.org> --- Changes in v4: - Remove gpio entity, it is not needed. - Use unit->gpio.irq in free_irq to make smatch happy. - Link to v3: https://lore.kernel.org/r/20241112-uvc-subdev-v3-0-0ea573d41a18@chromium.org Changes in v3: - CodeStyle (Thanks Sakari) - Re-implement as input device - Make the code depend on UVC_INPUT_EVDEV - Link to v2: https://lore.kernel.org/r/20241108-uvc-subdev-v2-0-85d8a051a3d3@chromium.org Changes in v2: - Rebase on top of https://patchwork.linuxtv.org/project/linux-media/patch/20241106-uvc-crashr… - Create uvc_gpio_cleanup and uvc_gpio_deinit - Refactor quirk: do not disable irq - Change define number for MEDIA_ENT_F_GPIO - Link to v1: https://lore.kernel.org/r/20241031-uvc-subdev-v1-0-a68331cedd72@chromium.org --- Ricardo Ribalda (7): media: uvcvideo: Fix crash during unbind if gpio unit is in use media: uvcvideo: Factor out gpio functions to its own file media: uvcvideo: Re-implement privacy GPIO as an input device Revert "media: uvcvideo: Allow entity-defined get_info and get_cur" media: uvcvideo: Introduce UVC_QUIRK_PRIVACY_DURING_STREAM media: uvcvideo: Make gpio_unit entity-less media: uvcvideo: Remove UVC_EXT_GPIO entity drivers/media/usb/uvc/Kconfig | 2 +- drivers/media/usb/uvc/Makefile | 3 + drivers/media/usb/uvc/uvc_ctrl.c | 40 ++--------- drivers/media/usb/uvc/uvc_driver.c | 123 ++-------------------------------- drivers/media/usb/uvc/uvc_entity.c | 7 +- drivers/media/usb/uvc/uvc_gpio.c | 134 +++++++++++++++++++++++++++++++++++++ drivers/media/usb/uvc/uvc_status.c | 13 +++- drivers/media/usb/uvc/uvc_video.c | 4 ++ drivers/media/usb/uvc/uvcvideo.h | 43 +++++++----- 9 files changed, 195 insertions(+), 174 deletions(-) --- base-commit: 72ad4ff638047bbbdf3232178fea4bec1f429319 change-id: 20241030-uvc-subdev-89f4467a00b5 Best regards, -- Ricardo Ribalda <ribalda(a)chromium.org>

6 months, 2 weeks

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[PATCH 5.15] Revert "drivers: clk: zynqmp: update divider round rate logic"

by jguittet.opensource＠witekio.com

From: Joel Guittet <jguittet(a)witekio.com> This reverts commit 9117fc44fd3a9538261e530ba5a022dfc9519620 which is commit 1fe15be1fb613534ecbac5f8c3f8744f757d237d upstream. It is reported to cause regressions in the 5.15.y tree, so revert it for now. Link: https://www.spinics.net/lists/kernel/msg5397998.html Signed-off-by: Joel Guittet <jguittet.opensource(a)witekio.com> --- drivers/clk/zynqmp/divider.c | 66 +++++++++++++++++++++++++++++++++--- 1 file changed, 61 insertions(+), 5 deletions(-) diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c index e25c76ff2739..47a199346ddf 100644 --- a/drivers/clk/zynqmp/divider.c +++ b/drivers/clk/zynqmp/divider.c @@ -110,6 +110,52 @@ static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw, return DIV_ROUND_UP_ULL(parent_rate, value); } +static void zynqmp_get_divider2_val(struct clk_hw *hw, + unsigned long rate, + struct zynqmp_clk_divider *divider, + u32 *bestdiv) +{ + int div1; + int div2; + long error = LONG_MAX; + unsigned long div1_prate; + struct clk_hw *div1_parent_hw; + struct zynqmp_clk_divider *pdivider; + struct clk_hw *div2_parent_hw = clk_hw_get_parent(hw); + + if (!div2_parent_hw) + return; + + pdivider = to_zynqmp_clk_divider(div2_parent_hw); + if (!pdivider) + return; + + div1_parent_hw = clk_hw_get_parent(div2_parent_hw); + if (!div1_parent_hw) + return; + + div1_prate = clk_hw_get_rate(div1_parent_hw); + *bestdiv = 1; + for (div1 = 1; div1 <= pdivider->max_div;) { + for (div2 = 1; div2 <= divider->max_div;) { + long new_error = ((div1_prate / div1) / div2) - rate; + + if (abs(new_error) < abs(error)) { + *bestdiv = div2; + error = new_error; + } + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + div2 = div2 << 1; + else + div2++; + } + if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO) + div1 = div1 << 1; + else + div1++; + } +} + /** * zynqmp_clk_divider_round_rate() - Round rate of divider clock * @hw: handle between common and hardware-specific interfaces @@ -128,7 +174,6 @@ static long zynqmp_clk_divider_round_rate(struct clk_hw *hw, u32 div_type = divider->div_type; u32 bestdiv; int ret; - u8 width; /* if read only, just return current value */ if (divider->flags & CLK_DIVIDER_READ_ONLY) { @@ -148,12 +193,23 @@ static long zynqmp_clk_divider_round_rate(struct clk_hw *hw, return DIV_ROUND_UP_ULL((u64)*prate, bestdiv); } - width = fls(divider->max_div); + bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags); + + /* + * In case of two divisors, compute best divider values and return + * divider2 value based on compute value. div1 will be automatically + * set to optimum based on required total divider value. + */ + if (div_type == TYPE_DIV2 && + (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) { + zynqmp_get_divider2_val(hw, rate, divider, &bestdiv); + } - rate = divider_round_rate(hw, rate, prate, NULL, width, divider->flags); + if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac) + bestdiv = rate % *prate ? 1 : bestdiv; - if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate)) - *prate = rate; + bestdiv = min_t(u32, bestdiv, divider->max_div); + *prate = rate * bestdiv; return rate; } -- 2.25.1

6 months, 2 weeks

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[PATCH 6.1.y] mptcp: fix possible integer overflow in mptcp_reset_tout_timer

by Matthieu Baerts (NGI0)

From: Dmitry Kandybka <d.kandybka(a)gmail.com> commit b169e76ebad22cbd055101ee5aa1a7bed0e66606 upstream. In 'mptcp_reset_tout_timer', promote 'probe_timestamp' to unsigned long to avoid possible integer overflow. Compile tested only. Found by Linux Verification Center (linuxtesting.org) with SVACE. Signed-off-by: Dmitry Kandybka <d.kandybka(a)gmail.com> Link: https://patch.msgid.link/20241107103657.1560536-1-d.kandybka@gmail.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> [ Conflict in this version because commit d866ae9aaa43 ("mptcp: add a new sysctl for make after break timeout") is not in this version, and replaced TCP_TIMEWAIT_LEN in the expression. The fix can still be applied the same way: by forcing a cast to unsigned long for the first item. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- net/mptcp/protocol.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 1acd4e37a0ea..370afcac2623 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2708,8 +2708,8 @@ void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout) if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp) return; - close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + - TCP_TIMEWAIT_LEN; + close_timeout = (unsigned long)inet_csk(sk)->icsk_mtup.probe_timestamp - + tcp_jiffies32 + jiffies + TCP_TIMEWAIT_LEN; /* the close timeout takes precedence on the fail one, and here at least one of * them is active -- 2.45.2

6 months, 2 weeks

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[PATCH 5.4] nvme: fix metadata handling in nvme-passthrough

by Hagar Hemdan

From: Puranjay Mohan <pjy(a)amazon.com> [ Upstream commit 7c2fd76048e95dd267055b5f5e0a48e6e7c81fd9 ] On an NVMe namespace that does not support metadata, it is possible to send an IO command with metadata through io-passthru. This allows issues like [1] to trigger in the completion code path. nvme_map_user_request() doesn't check if the namespace supports metadata before sending it forward. It also allows admin commands with metadata to be processed as it ignores metadata when bdev == NULL and may report success. Reject an IO command with metadata when the NVMe namespace doesn't support it and reject an admin command if it has metadata. [1] https://lore.kernel.org/all/mb61pcylvnym8.fsf@amazon.com/ Suggested-by: Christoph Hellwig <hch(a)lst.de> Signed-off-by: Puranjay Mohan <pjy(a)amazon.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Reviewed-by: Sagi Grimberg <sagi(a)grimberg.me> Reviewed-by: Anuj Gupta <anuj20.g(a)samsung.com> Signed-off-by: Keith Busch <kbusch(a)kernel.org> [ Move the changes from nvme_map_user_request() to nvme_submit_user_cmd() to make it work on 5.4 ] Signed-off-by: Hagar Hemdan <hagarhem(a)amazon.com> --- drivers/nvme/host/core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 0676637e1eab..a841fd4929ad 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -921,11 +921,16 @@ static int nvme_submit_user_cmd(struct request_queue *q, bool write = nvme_is_write(cmd); struct nvme_ns *ns = q->queuedata; struct gendisk *disk = ns ? ns->disk : NULL; + bool supports_metadata = disk && blk_get_integrity(disk); + bool has_metadata = meta_buffer && meta_len; struct request *req; struct bio *bio = NULL; void *meta = NULL; int ret; + if (has_metadata && !supports_metadata) + return -EINVAL; + req = nvme_alloc_request(q, cmd, 0, NVME_QID_ANY); if (IS_ERR(req)) return PTR_ERR(req); @@ -940,7 +945,7 @@ static int nvme_submit_user_cmd(struct request_queue *q, goto out; bio = req->bio; bio->bi_disk = disk; - if (disk && meta_buffer && meta_len) { + if (has_metadata) { meta = nvme_add_user_metadata(bio, meta_buffer, meta_len, meta_seed, write); if (IS_ERR(meta)) { -- 2.40.1

6 months, 2 weeks

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[PATCH 4.19] nvme: fix metadata handling in nvme-passthrough

by Hagar Hemdan

From: Puranjay Mohan <pjy(a)amazon.com> [ Upstream commit 7c2fd76048e95dd267055b5f5e0a48e6e7c81fd9 ] On an NVMe namespace that does not support metadata, it is possible to send an IO command with metadata through io-passthru. This allows issues like [1] to trigger in the completion code path. nvme_map_user_request() doesn't check if the namespace supports metadata before sending it forward. It also allows admin commands with metadata to be processed as it ignores metadata when bdev == NULL and may report success. Reject an IO command with metadata when the NVMe namespace doesn't support it and reject an admin command if it has metadata. [1] https://lore.kernel.org/all/mb61pcylvnym8.fsf@amazon.com/ Suggested-by: Christoph Hellwig <hch(a)lst.de> Signed-off-by: Puranjay Mohan <pjy(a)amazon.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Reviewed-by: Sagi Grimberg <sagi(a)grimberg.me> Reviewed-by: Anuj Gupta <anuj20.g(a)samsung.com> Signed-off-by: Keith Busch <kbusch(a)kernel.org> [ Move the changes from nvme_map_user_request() to nvme_submit_user_cmd() to make it work on 4.19 ] Signed-off-by: Hagar Hemdan <hagarhem(a)amazon.com> --- drivers/nvme/host/core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 6adff541282b..fcf062f3b507 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -802,11 +802,16 @@ static int nvme_submit_user_cmd(struct request_queue *q, bool write = nvme_is_write(cmd); struct nvme_ns *ns = q->queuedata; struct gendisk *disk = ns ? ns->disk : NULL; + bool supports_metadata = disk && blk_get_integrity(disk); + bool has_metadata = meta_buffer && meta_len; struct request *req; struct bio *bio = NULL; void *meta = NULL; int ret; + if (has_metadata && !supports_metadata) + return -EINVAL; + req = nvme_alloc_request(q, cmd, 0, NVME_QID_ANY); if (IS_ERR(req)) return PTR_ERR(req); @@ -821,7 +826,7 @@ static int nvme_submit_user_cmd(struct request_queue *q, goto out; bio = req->bio; bio->bi_disk = disk; - if (disk && meta_buffer && meta_len) { + if (has_metadata) { meta = nvme_add_user_metadata(bio, meta_buffer, meta_len, meta_seed, write); if (IS_ERR(meta)) { -- 2.40.1

6 months, 2 weeks

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[PATCH 6.6.y] mptcp: fix possible integer overflow in mptcp_reset_tout_timer

by Matthieu Baerts (NGI0)

From: Dmitry Kandybka <d.kandybka(a)gmail.com> commit b169e76ebad22cbd055101ee5aa1a7bed0e66606 upstream. In 'mptcp_reset_tout_timer', promote 'probe_timestamp' to unsigned long to avoid possible integer overflow. Compile tested only. Found by Linux Verification Center (linuxtesting.org) with SVACE. Signed-off-by: Dmitry Kandybka <d.kandybka(a)gmail.com> Link: https://patch.msgid.link/20241107103657.1560536-1-d.kandybka@gmail.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> [ Conflict in this version because commit d866ae9aaa43 ("mptcp: add a new sysctl for make after break timeout") is not in this version, and replaced TCP_TIMEWAIT_LEN in the expression. The fix can still be applied the same way: by forcing a cast to unsigned long for the first item. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- net/mptcp/protocol.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index b8357d7c6b3a..01f6ce970918 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2691,8 +2691,8 @@ void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout) if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp) return; - close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + - TCP_TIMEWAIT_LEN; + close_timeout = (unsigned long)inet_csk(sk)->icsk_mtup.probe_timestamp - + tcp_jiffies32 + jiffies + TCP_TIMEWAIT_LEN; /* the close timeout takes precedence on the fail one, and here at least one of * them is active -- 2.45.2

6 months, 2 weeks

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[PATCH AUTOSEL 6.6 1/4] uprobes: sanitiize xol_free_insn_slot()

by Sasha Levin

From: Oleg Nesterov <oleg(a)redhat.com> [ Upstream commit c7b4133c48445dde789ed30b19ccb0448c7593f7 ] 1. Clear utask->xol_vaddr unconditionally, even if this addr is not valid, xol_free_insn_slot() should never return with utask->xol_vaddr != NULL. 2. Add a comment to explain why do we need to validate slot_addr. 3. Simplify the validation above. We can simply check offset < PAGE_SIZE, unsigned underflows are fine, it should work if slot_addr < area->vaddr. 4. Kill the unnecessary "slot_nr >= UINSNS_PER_PAGE" check, slot_nr must be valid if offset < PAGE_SIZE. The next patches will cleanup this function even more. Signed-off-by: Oleg Nesterov <oleg(a)redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://lore.kernel.org/r/20240929144235.GA9471@redhat.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- kernel/events/uprobes.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 6dac0b5798213..5ce3d189e33c2 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1629,8 +1629,8 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe) static void xol_free_insn_slot(struct task_struct *tsk) { struct xol_area *area; - unsigned long vma_end; unsigned long slot_addr; + unsigned long offset; if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) return; @@ -1639,24 +1639,21 @@ static void xol_free_insn_slot(struct task_struct *tsk) if (unlikely(!slot_addr)) return; + tsk->utask->xol_vaddr = 0; area = tsk->mm->uprobes_state.xol_area; - vma_end = area->vaddr + PAGE_SIZE; - if (area->vaddr <= slot_addr && slot_addr < vma_end) { - unsigned long offset; - int slot_nr; - - offset = slot_addr - area->vaddr; - slot_nr = offset / UPROBE_XOL_SLOT_BYTES; - if (slot_nr >= UINSNS_PER_PAGE) - return; + offset = slot_addr - area->vaddr; + /* + * slot_addr must fit into [area->vaddr, area->vaddr + PAGE_SIZE). + * This check can only fail if the "[uprobes]" vma was mremap'ed. + */ + if (offset < PAGE_SIZE) { + int slot_nr = offset / UPROBE_XOL_SLOT_BYTES; clear_bit(slot_nr, area->bitmap); atomic_dec(&area->slot_count); smp_mb__after_atomic(); /* pairs with prepare_to_wait() */ if (waitqueue_active(&area->wq)) wake_up(&area->wq); - - tsk->utask->xol_vaddr = 0; } } -- 2.43.0

6 months, 2 weeks

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[PATCH AUTOSEL 6.11 1/5] uprobes: sanitiize xol_free_insn_slot()

by Sasha Levin

From: Oleg Nesterov <oleg(a)redhat.com> [ Upstream commit c7b4133c48445dde789ed30b19ccb0448c7593f7 ] 1. Clear utask->xol_vaddr unconditionally, even if this addr is not valid, xol_free_insn_slot() should never return with utask->xol_vaddr != NULL. 2. Add a comment to explain why do we need to validate slot_addr. 3. Simplify the validation above. We can simply check offset < PAGE_SIZE, unsigned underflows are fine, it should work if slot_addr < area->vaddr. 4. Kill the unnecessary "slot_nr >= UINSNS_PER_PAGE" check, slot_nr must be valid if offset < PAGE_SIZE. The next patches will cleanup this function even more. Signed-off-by: Oleg Nesterov <oleg(a)redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://lore.kernel.org/r/20240929144235.GA9471@redhat.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- kernel/events/uprobes.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 56cd0c7f516d3..5df99a1223c22 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1639,8 +1639,8 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe) static void xol_free_insn_slot(struct task_struct *tsk) { struct xol_area *area; - unsigned long vma_end; unsigned long slot_addr; + unsigned long offset; if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) return; @@ -1649,24 +1649,21 @@ static void xol_free_insn_slot(struct task_struct *tsk) if (unlikely(!slot_addr)) return; + tsk->utask->xol_vaddr = 0; area = tsk->mm->uprobes_state.xol_area; - vma_end = area->vaddr + PAGE_SIZE; - if (area->vaddr <= slot_addr && slot_addr < vma_end) { - unsigned long offset; - int slot_nr; - - offset = slot_addr - area->vaddr; - slot_nr = offset / UPROBE_XOL_SLOT_BYTES; - if (slot_nr >= UINSNS_PER_PAGE) - return; + offset = slot_addr - area->vaddr; + /* + * slot_addr must fit into [area->vaddr, area->vaddr + PAGE_SIZE). + * This check can only fail if the "[uprobes]" vma was mremap'ed. + */ + if (offset < PAGE_SIZE) { + int slot_nr = offset / UPROBE_XOL_SLOT_BYTES; clear_bit(slot_nr, area->bitmap); atomic_dec(&area->slot_count); smp_mb__after_atomic(); /* pairs with prepare_to_wait() */ if (waitqueue_active(&area->wq)) wake_up(&area->wq); - - tsk->utask->xol_vaddr = 0; } } -- 2.43.0

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