From: Schspa Shi schspa@gmail.com

[ Upstream commit 6641085e8d7b3f061911517f79a2a15a0a21b97b ]

On buffer resize failure, vfio_info_cap_add() will free the buffer, report zero for the size, and return -ENOMEM. As additional hardening, also clear the buffer pointer to prevent any chance of a double free.

Signed-off-by: Schspa Shi schspa@gmail.com Reviewed-by: Cornelia Huck cohuck@redhat.com Link: https://lore.kernel.org/r/20220629022948.55608-1-schspa@gmail.com Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vfio/vfio.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 881fc3a55edc..5798965f42b5 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1793,6 +1793,7 @@ struct vfio_info_cap_header *vfio_info_cap_add(struct vfio_info_cap *caps, buf = krealloc(caps->buf, caps->size + size, GFP_KERNEL); if (!buf) { kfree(caps->buf); + caps->buf = NULL; caps->size = 0; return ERR_PTR(-ENOMEM); }

From: Takashi Iwai tiwai@suse.de

[ Upstream commit ef34a0ae7a2654bc9e58675e36898217fb2799d8 ]

Currently the call of kill_fasync() from an interrupt handler might lead to potential spin deadlocks, as spotted by syzkaller. Unfortunately, it's not so trivial to fix this lock chain as it's involved with the tasklist_lock that is touched in allover places.

As a temporary workaround, this patch provides the way to defer the async signal notification in a work. The new helper functions, snd_fasync_helper() and snd_kill_faync() are replacements for fasync_helper() and kill_fasync(), respectively. In addition, snd_fasync_free() needs to be called at the destructor of the relevant file object.

Link: https://lore.kernel.org/r/20220728125945.29533-2-tiwai@suse.de Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- include/sound/core.h | 8 ++++ sound/core/misc.c | 94 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 102 insertions(+)

diff --git a/include/sound/core.h b/include/sound/core.h index 31079ea5e484..d5d0e5e53920 100644 --- a/include/sound/core.h +++ b/include/sound/core.h @@ -457,4 +457,12 @@ snd_pci_quirk_lookup_id(u16 vendor, u16 device, } #endif

+/* async signal helpers */ +struct snd_fasync; + +int snd_fasync_helper(int fd, struct file *file, int on, + struct snd_fasync **fasyncp); +void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll); +void snd_fasync_free(struct snd_fasync *fasync); + #endif /* __SOUND_CORE_H */ diff --git a/sound/core/misc.c b/sound/core/misc.c index f2e8226c88fb..efe26b8ca57f 100644 --- a/sound/core/misc.c +++ b/sound/core/misc.c @@ -25,6 +25,7 @@ #include <linux/time.h> #include <linux/slab.h> #include <linux/ioport.h> +#include <linux/fs.h> #include <sound/core.h>

#ifdef CONFIG_SND_DEBUG @@ -153,3 +154,96 @@ snd_pci_quirk_lookup(struct pci_dev *pci, const struct snd_pci_quirk *list) } EXPORT_SYMBOL(snd_pci_quirk_lookup); #endif + +/* + * Deferred async signal helpers + * + * Below are a few helper functions to wrap the async signal handling + * in the deferred work. The main purpose is to avoid the messy deadlock + * around tasklist_lock and co at the kill_fasync() invocation. + * fasync_helper() and kill_fasync() are replaced with snd_fasync_helper() + * and snd_kill_fasync(), respectively. In addition, snd_fasync_free() has + * to be called at releasing the relevant file object. + */ +struct snd_fasync { + struct fasync_struct *fasync; + int signal; + int poll; + int on; + struct list_head list; +}; + +static DEFINE_SPINLOCK(snd_fasync_lock); +static LIST_HEAD(snd_fasync_list); + +static void snd_fasync_work_fn(struct work_struct *work) +{ + struct snd_fasync *fasync; + + spin_lock_irq(&snd_fasync_lock); + while (!list_empty(&snd_fasync_list)) { + fasync = list_first_entry(&snd_fasync_list, struct snd_fasync, list); + list_del_init(&fasync->list); + spin_unlock_irq(&snd_fasync_lock); + if (fasync->on) + kill_fasync(&fasync->fasync, fasync->signal, fasync->poll); + spin_lock_irq(&snd_fasync_lock); + } + spin_unlock_irq(&snd_fasync_lock); +} + +static DECLARE_WORK(snd_fasync_work, snd_fasync_work_fn); + +int snd_fasync_helper(int fd, struct file *file, int on, + struct snd_fasync **fasyncp) +{ + struct snd_fasync *fasync = NULL; + + if (on) { + fasync = kzalloc(sizeof(*fasync), GFP_KERNEL); + if (!fasync) + return -ENOMEM; + INIT_LIST_HEAD(&fasync->list); + } + + spin_lock_irq(&snd_fasync_lock); + if (*fasyncp) { + kfree(fasync); + fasync = *fasyncp; + } else { + if (!fasync) { + spin_unlock_irq(&snd_fasync_lock); + return 0; + } + *fasyncp = fasync; + } + fasync->on = on; + spin_unlock_irq(&snd_fasync_lock); + return fasync_helper(fd, file, on, &fasync->fasync); +} +EXPORT_SYMBOL_GPL(snd_fasync_helper); + +void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll) +{ + unsigned long flags; + + if (!fasync || !fasync->on) + return; + spin_lock_irqsave(&snd_fasync_lock, flags); + fasync->signal = signal; + fasync->poll = poll; + list_move(&fasync->list, &snd_fasync_list); + schedule_work(&snd_fasync_work); + spin_unlock_irqrestore(&snd_fasync_lock, flags); +} +EXPORT_SYMBOL_GPL(snd_kill_fasync); + +void snd_fasync_free(struct snd_fasync *fasync) +{ + if (!fasync) + return; + fasync->on = 0; + flush_work(&snd_fasync_work); + kfree(fasync); +} +EXPORT_SYMBOL_GPL(snd_fasync_free);

From: Zhouyi Zhou zhouzhouyi@gmail.com

[ Upstream commit ca829e05d3d4f728810cc5e4b468d9ebc7745eb3 ]

On 64-bit, calling jump_label_init() in setup_feature_keys() is too late because static keys may be used in subroutines of parse_early_param() which is again subroutine of early_init_devtree().

For example booting with "threadirqs":

static_key_enable_cpuslocked(): static key '0xc000000002953260' used before call to jump_label_init() WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:166 static_key_enable_cpuslocked+0xfc/0x120 ... NIP static_key_enable_cpuslocked+0xfc/0x120 LR static_key_enable_cpuslocked+0xf8/0x120 Call Trace: static_key_enable_cpuslocked+0xf8/0x120 (unreliable) static_key_enable+0x30/0x50 setup_forced_irqthreads+0x28/0x40 do_early_param+0xa0/0x108 parse_args+0x290/0x4e0 parse_early_options+0x48/0x5c parse_early_param+0x58/0x84 early_init_devtree+0xd4/0x518 early_setup+0xb4/0x214

So call jump_label_init() just before parse_early_param() in early_init_devtree().

Suggested-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Zhouyi Zhou zhouzhouyi@gmail.com [mpe: Add call trace to change log and minor wording edits.] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220726015747.11754-1-zhouzhouyi@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/prom.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index 11b4ecec04ee..1413d72689d2 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -682,6 +682,13 @@ void __init early_init_devtree(void *params) of_scan_flat_dt(early_init_dt_scan_root, NULL); of_scan_flat_dt(early_init_dt_scan_memory_ppc, NULL);

+ /* + * As generic code authors expect to be able to use static keys + * in early_param() handlers, we initialize the static keys just + * before parsing early params (it's fine to call jump_label_init() + * more than once). + */ + jump_label_init(); parse_early_param();

/* make sure we've parsed cmdline for mem= before this */

From: Nathan Chancellor nathan@kernel.org

[ Upstream commit 74de14fe05dd6b151d73cb0c73c8ec874cbdcde6 ]

When CONFIG_XPA is enabled, Clang warns:

arch/mips/mm/tlbex.c:629:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] if (cpu_has_rixi && !!_PAGE_NO_EXEC) { ^ arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) ^ arch/mips/mm/tlbex.c:2568:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] if (!cpu_has_rixi || !_PAGE_NO_EXEC) { ^ arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) ^ 2 errors generated.

_PAGE_NO_EXEC can be '0' or '1 << _PAGE_NO_EXEC_SHIFT' depending on the build and runtime configuration, which is what the negation operators are trying to convey. To silence the warning, explicitly compare against 0 so the result of the '<<' operator is not implicitly converted to a boolean.

According to its documentation, GCC enables -Wint-in-bool-context with -Wall but this warning is not visible when building the same configuration with GCC. It appears GCC only warns when compiling C++, not C, although the documentation makes no note of this: https://godbolt.org/z/x39q3brxf

Reported-by: Sudip Mukherjee (Codethink) sudipm.mukherjee@gmail.com Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/mips/mm/tlbex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index f625fd20b21e..65fed205383e 100644 --- a/arch/mips/mm/tlbex.c +++ b/arch/mips/mm/tlbex.c @@ -637,7 +637,7 @@ static __maybe_unused void build_convert_pte_to_entrylo(u32 **p, return; }

- if (cpu_has_rixi && !!_PAGE_NO_EXEC) { + if (cpu_has_rixi && _PAGE_NO_EXEC != 0) { if (fill_includes_sw_bits) { UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL)); } else { @@ -2518,7 +2518,7 @@ static void check_pabits(void) unsigned long entry; unsigned pabits, fillbits;

- if (!cpu_has_rixi || !_PAGE_NO_EXEC) { + if (!cpu_has_rixi || _PAGE_NO_EXEC == 0) { /* * We'll only be making use of the fact that we can rotate bits * into the fill if the CPU supports RIXI, so don't bother