kernel/linux.git/sound/core, branch v6.12.80

ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()

2026-03-25T10:08:30+00:00

commit 9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6 upstream. In the drain loop, the local variable 'runtime' is reassigned to a linked stream's runtime (runtime = s->runtime at line 2157). After releasing the stream lock at line 2169, the code accesses runtime->no_period_wakeup, runtime->rate, and runtime->buffer_size (lines 2170-2178) — all referencing the linked stream's runtime without any lock or refcount protecting its lifetime. A concurrent close() on the linked stream's fd triggers snd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private() → snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime). No synchronization prevents kfree(runtime) from completing while the drain path dereferences the stale pointer. Fix by caching the needed runtime fields (no_period_wakeup, rate, buffer_size) into local variables while still holding the stream lock, and using the cached values after the lock is released. Fixes: f2b3614cefb6 ("ALSA: PCM - Don't check DMA time-out too shortly") Cc: stable@vger.kernel.org Signed-off-by: Mehul Rao Link: https://patch.msgid.link/20260305193508.311096-1-mehulrao@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: pcm: Revert bufs move in snd_pcm_xfern_frames_ioctl()

2026-03-04T12:22:00+00:00

[ Upstream commit 0585c53b21541cd6b17ad5ab41b371a0d52e358c ] When building with clang older than 17 targeting architectures that use asm goto for their get_user() and put_user(), such as arm64, after commit f3d233daf011 ("ALSA: pcm: Relax __free() variable declarations"), there are bogus errors around skipping over a variable declared with the cleanup attribute: sound/core/pcm_native.c:3308:6: error: cannot jump from this asm goto statement to one of its possible targets if (put_user(result, &_xfern->result)) ^ ... arch/arm64/include/asm/uaccess.h:298:2: note: expanded from macro '__put_mem_asm' asm goto( ^ sound/core/pcm_native.c:3295:6: note: possible target of asm goto statement if (put_user(0, &_xfern->result)) ^ ... sound/core/pcm_native.c:3300:8: note: jump exits scope of variable with __attribute__((cleanup)) void *bufs __free(kfree) = ^ clang-17 fixed a bug in clang's jump scope checker [1] where all labels in a function were checked as valid targets for all asm goto instances in a function, regardless of whether they were actual targets in a paricular asm goto's provided list of labels. To workaround this, revert the change done to snd_pcm_xfern_frames_ioctl() by commit f3d233daf011 ("ALSA: pcm: Relax __free() variable declarations") to avoid a variable declared with cleanup from existing between multiple uses of asm goto. There are no other uses of cleanup in this function so there should be low risk from moving this variable back to the top of the function. Link: https://github.com/ClangBuiltLinux/linux/issues/1886 [1] Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202512190802.i4Jzbcsl-lkp@intel.com/ Signed-off-by: Nathan Chancellor Link: https://patch.msgid.link/20260106-pcm_native-revert-var-move-free-for-old-clang-v1-1-06a03693423d@kernel.org Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: mixer: oss: Add card disconnect checkpoints

2026-03-04T12:21:10+00:00

[ Upstream commit 084d5d44418148662365eced3e126ad1a81ee3e2 ] ALSA OSS mixer layer calls the kcontrol ops rather individually, and pending calls might be not always caught at disconnecting the device. For avoiding the potential UAF scenarios, add sanity checks of the card disconnection at each entry point of OSS mixer accesses. The rwsem is taken just before that check, hence the rest context should be covered by that properly. Link: https://patch.msgid.link/20260209121212.171430-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: vmaster: Relax __free() variable declarations

2026-03-04T12:19:50+00:00

[ Upstream commit 3b7c7bda39e1e48f926fb3d280a5f5d20a939857 ] We used to have a variable declaration with __free() initialized with NULL. This was to keep the old coding style rule, but recently it's relaxed and rather recommends to follow the new rule to declare in place of use for __free() -- which avoids potential deadlocks or UAFs with nested cleanups. Although the current code has no bug, per se, let's follow the new standard and move the declaration to the place of assignment (or directly assign the allocated result) instead of NULL initializations. Fixes: fb9e197f3f27 ("ALSA: vmaster: Use automatic cleanup of kfree()") Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20251216140634.171890-9-tiwai@suse.de Signed-off-by: Sasha Levin

ALSA: pcm: Relax __free() variable declarations

2026-03-04T12:19:50+00:00

[ Upstream commit f3d233daf011abbad2f6ebd0e545b42d2f378a4f ] We used to have a variable declaration with __free() initialized with NULL. This was to keep the old coding style rule, but recently it's relaxed and rather recommends to follow the new rule to declare in place of use for __free() -- which avoids potential deadlocks or UAFs with nested cleanups. Although the current code has no bug, per se, let's follow the new standard and move the declaration to the place of assignment (or directly assign the allocated result) instead of NULL initializations. Fixes: ae9213984864 ("ALSA: pcm: Use automatic cleanup of kfree()") Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20251216140634.171890-4-tiwai@suse.de Signed-off-by: Sasha Levin

ALSA: pcm: use new array-copying-wrapper

2026-03-04T12:19:50+00:00

[ Upstream commit 519b2b14bef70922bd64117a978ea7f2a683b75b ] This is found by our static analysis tool. pcm_native.c utilizes memdup_user() to copy an array from userspace. There is a new wrapper, specifically designed for copying arrays. Use this one instead. This is similar to the commit 3e91a38de1dc ("fbdev: viafb: use new array-copying-wrapper"). Signed-off-by: Chenyuan Yang Link: https://patch.msgid.link/20250127160655.3119470-1-cy1yang@outlook.com Signed-off-by: Takashi Iwai Stable-dep-of: f3d233daf011 ("ALSA: pcm: Relax __free() variable declarations") Signed-off-by: Sasha Levin

ALSA: pcm: Improve the fix for race of buffer access at PCM OSS layer

2026-01-23T10:18:43+00:00

commit 47c27c9c9c720bc93fdc69605d0ecd9382e99047 upstream. Handle the error code from snd_pcm_buffer_access_lock() in snd_pcm_runtime_buffer_set_silence() function. Found by Alexandros Panagiotou Fixes: 93a81ca06577 ("ALSA: pcm: Fix race of buffer access at PCM OSS layer") Cc: stable@vger.kernel.org # 6.15 Signed-off-by: Jaroslav Kysela Link: https://patch.msgid.link/20260107213642.332954-1-perex@perex.cz Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: pcm: Disable bottom softirqs as part of spin_lock_irq() on PREEMPT_RT

2025-10-15T10:00:12+00:00

[ Upstream commit 9fc4a3da9a0259a0500848b5d8657918efde176b ] snd_pcm_group_lock_irq() acquires a spinlock_t and disables interrupts via spin_lock_irq(). This also implicitly disables the handling of softirqs such as TIMER_SOFTIRQ. On PREEMPT_RT softirqs are preemptible and spin_lock_irq() does not disable them. That means a timer can be invoked during spin_lock_irq() on the same CPU. Due to synchronisations reasons local_bh_disable() has a per-CPU lock named softirq_ctrl.lock which synchronizes individual softirq against each other. syz-bot managed to trigger a lockdep report where softirq_ctrl.lock is acquired in hrtimer_cancel() in addition to hrtimer_run_softirq(). This is a possible deadlock. The softirq_ctrl.lock can not be made part of spin_lock_irq() as this would lead to too much synchronisation against individual threads on the system. To avoid the possible deadlock, softirqs must be manually disabled before the lock is acquired. Disable softirqs before the lock is acquired on PREEMPT_RT. Reported-by: syzbot+10b4363fb0f46527f3f3@syzkaller.appspotmail.com Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: timer: fix ida_free call while not allocated

2025-08-28T14:31:15+00:00

[ Upstream commit 5003a65790ed66be882d1987cc2ca86af0de3db1 ] In the snd_utimer_create() function, if the kasprintf() function return NULL, snd_utimer_put_id() will be called, finally use ida_free() to free the unallocated id 0. the syzkaller reported the following information: ------------[ cut here ]------------ ida_free called for id=0 which is not allocated. WARNING: CPU: 1 PID: 1286 at lib/idr.c:592 ida_free+0x1fd/0x2f0 lib/idr.c:592 Modules linked in: CPU: 1 UID: 0 PID: 1286 Comm: syz-executor164 Not tainted 6.15.8 #3 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.fc42 04/01/2014 RIP: 0010:ida_free+0x1fd/0x2f0 lib/idr.c:592 Code: f8 fc 41 83 fc 3e 76 69 e8 70 b2 f8 (...) RSP: 0018:ffffc900007f79c8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 1ffff920000fef3b RCX: ffffffff872176a5 RDX: ffff88800369d200 RSI: 0000000000000000 RDI: ffff88800369d200 RBP: 0000000000000000 R08: ffffffff87ba60a5 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f6f1abc1740(0000) GS:ffff8880d76a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6f1ad7a784 CR3: 000000007a6e2000 CR4: 00000000000006f0 Call Trace: snd_utimer_put_id sound/core/timer.c:2043 [inline] [snd_timer] snd_utimer_create+0x59b/0x6a0 sound/core/timer.c:2184 [snd_timer] snd_utimer_ioctl_create sound/core/timer.c:2202 [inline] [snd_timer] __snd_timer_user_ioctl.isra.0+0x724/0x1340 sound/core/timer.c:2287 [snd_timer] snd_timer_user_ioctl+0x75/0xc0 sound/core/timer.c:2298 [snd_timer] vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x198/0x200 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x7b/0x160 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e [...] The utimer->id should be set properly before the kasprintf() function, ensures the snd_utimer_put_id() function will free the allocated id. Fixes: 37745918e0e75 ("ALSA: timer: Introduce virtual userspace-driven timers") Signed-off-by: Dewei Meng Link: https://patch.msgid.link/20250821014317.40786-1-mengdewei@cqsoftware.com.cn Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: pcm: Rewrite recalculate_boundary() to avoid costly loop

2025-08-20T16:30:27+00:00

[ Upstream commit 92f59aeb13252265c20e7aef1379a8080c57e0a2 ] At the time being recalculate_boundary() is implemented with a loop which shows up as costly in a perf profile, as depicted by the annotate below: 0.00 : c057e934: 3d 40 7f ff lis r10,32767 0.03 : c057e938: 61 4a ff ff ori r10,r10,65535 0.21 : c057e93c: 7d 49 50 50 subf r10,r9,r10 5.39 : c057e940: 7d 3c 4b 78 mr r28,r9 2.11 : c057e944: 55 29 08 3c slwi r9,r9,1 3.04 : c057e948: 7c 09 50 40 cmplw r9,r10 2.47 : c057e94c: 40 81 ff f4 ble c057e940 Total: 13.2% on that simple loop. But what the loop does is to multiply the boundary by 2 until it is over the wanted border. This can be avoided by using fls() to get the boundary value order and shift it by the appropriate number of bits at once. This change provides the following profile: 0.04 : c057f6e8: 3d 20 7f ff lis r9,32767 0.02 : c057f6ec: 61 29 ff ff ori r9,r9,65535 0.34 : c057f6f0: 7d 5a 48 50 subf r10,r26,r9 0.23 : c057f6f4: 7c 1a 50 40 cmplw r26,r10 0.02 : c057f6f8: 41 81 00 20 bgt c057f718 0.26 : c057f6fc: 7f 47 00 34 cntlzw r7,r26 0.09 : c057f700: 7d 48 00 34 cntlzw r8,r10 0.22 : c057f704: 7d 08 38 50 subf r8,r8,r7 0.04 : c057f708: 7f 5a 40 30 slw r26,r26,r8 0.35 : c057f70c: 7c 0a d0 40 cmplw r10,r26 0.13 : c057f710: 40 80 05 f8 bge c057fd08 0.00 : c057f714: 57 5a f8 7e srwi r26,r26,1 Total: 1.7% with that loopless alternative. Signed-off-by: Christophe Leroy Link: https://patch.msgid.link/4836e2cde653eebaf2709ebe30eec736bb8c67fd.1749202237.git.christophe.leroy@csgroup.eu Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin