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* [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2)
@ 2025-08-29 18:38 syzbot
  2025-08-30  0:06 ` syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2025-08-29 18:38 UTC (permalink / raw)
  To: linux-kernel, linux-sound, perex, syzkaller-bugs, tiwai

Hello,

syzbot found the following issue on:

HEAD commit:    07d9df80082b Merge tag 'perf-tools-fixes-for-v6.17-2025-08..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17333fbc580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e
dashboard link: https://syzkaller.appspot.com/bug?extid=10b4363fb0f46527f3f3
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=160e9262580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17ed0242580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cdf0bbb7922b/disk-07d9df80.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1975bf771ed/vmlinux-07d9df80.xz
kernel image: https://storage.googleapis.com/syzbot-assets/942416e1bedd/bzImage-07d9df80.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+10b4363fb0f46527f3f3@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.48/6160 is trying to acquire lock:
ffff8880b8923d90 ((softirq_ctrl.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
ffff8880b8923d90 ((softirq_ctrl.lock)){+.+.}-{3:3}, at: __local_bh_disable_ip+0x264/0x400 kernel/softirq.c:168

but task is already holding lock:
ffff88802f930150 (&group->lock#2){+.+.}-{3:3}, at: __snd_pcm_lib_xfer+0x386/0x1ce0 sound/core/pcm_lib.c:2319

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&group->lock#2){+.+.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       rt_spin_lock+0x88/0x2c0 kernel/locking/spinlock_rt.c:56
       spin_lock include/linux/spinlock_rt.h:44 [inline]
       _snd_pcm_stream_lock_irqsave+0x7c/0xa0 sound/core/pcm_native.c:171
       class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:682 [inline]
       snd_pcm_period_elapsed+0x1e/0x80 sound/core/pcm_lib.c:1938
       dummy_hrtimer_callback+0x80/0x180 sound/drivers/dummy.c:386
       __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
       __hrtimer_run_queues+0x54f/0xd40 kernel/time/hrtimer.c:1825
       hrtimer_run_softirq+0x1a3/0x2e0 kernel/time/hrtimer.c:1842
       handle_softirqs+0x22c/0x710 kernel/softirq.c:579
       __do_softirq kernel/softirq.c:613 [inline]
       run_ktimerd+0xcf/0x190 kernel/softirq.c:1043
       smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #1 (&base->softirq_expiry_lock){+...}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       rt_spin_lock+0x88/0x2c0 kernel/locking/spinlock_rt.c:56
       spin_lock include/linux/spinlock_rt.h:44 [inline]
       hrtimer_cpu_base_lock_expiry kernel/time/hrtimer.c:1383 [inline]
       hrtimer_run_softirq+0x7c/0x2e0 kernel/time/hrtimer.c:1838
       handle_softirqs+0x22c/0x710 kernel/softirq.c:579
       __do_softirq kernel/softirq.c:613 [inline]
       run_ktimerd+0xcf/0x190 kernel/softirq.c:1043
       smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 ((softirq_ctrl.lock)){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
       reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385
       __lock_release kernel/locking/lockdep.c:5574 [inline]
       lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889
       __local_bh_enable_ip+0x10c/0x270 kernel/softirq.c:228
       hrtimer_cancel+0x39/0x60 kernel/time/hrtimer.c:1491
       dummy_hrtimer_stop+0xcf/0x100 sound/drivers/dummy.c:410
       snd_pcm_do_stop+0x12a/0x1c0 sound/core/pcm_native.c:1525
       snd_pcm_action_single sound/core/pcm_native.c:1305 [inline]
       snd_pcm_action+0xe4/0x240 sound/core/pcm_native.c:1388
       __snd_pcm_xrun+0x27f/0x7c0 sound/core/pcm_lib.c:180
       snd_pcm_update_state+0x342/0x430 sound/core/pcm_lib.c:224
       snd_pcm_update_hw_ptr0+0x10b2/0x1b00 sound/core/pcm_lib.c:493
       snd_pcm_update_hw_ptr sound/core/pcm_lib.c:499 [inline]
       __snd_pcm_lib_xfer+0x510/0x1ce0 sound/core/pcm_lib.c:2326
       snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241
       snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630
       snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline]
       snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline]
       snd_pcm_oss_write+0xba2/0x11a0 sound/core/oss/pcm_oss.c:2795
       vfs_write+0x284/0xb40 fs/read_write.c:684
       ksys_write+0x14b/0x260 fs/read_write.c:738
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  (softirq_ctrl.lock) --> &base->softirq_expiry_lock --> &group->lock#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&group->lock#2);
                               lock(&base->softirq_expiry_lock);
                               lock(&group->lock#2);
  lock((softirq_ctrl.lock));

 *** DEADLOCK ***

2 locks held by syz.0.48/6160:
 #0: ffff88802f930150 (&group->lock#2){+.+.}-{3:3}, at: __snd_pcm_lib_xfer+0x386/0x1ce0 sound/core/pcm_lib.c:2319
 #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1bb/0x2c0 kernel/locking/spinlock_rt.c:57

stack backtrace:
CPU: 1 UID: 0 PID: 6160 Comm: syz.0.48 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
 reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385
 __lock_release kernel/locking/lockdep.c:5574 [inline]
 lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889
 __local_bh_enable_ip+0x10c/0x270 kernel/softirq.c:228
 hrtimer_cancel+0x39/0x60 kernel/time/hrtimer.c:1491
 dummy_hrtimer_stop+0xcf/0x100 sound/drivers/dummy.c:410
 snd_pcm_do_stop+0x12a/0x1c0 sound/core/pcm_native.c:1525
 snd_pcm_action_single sound/core/pcm_native.c:1305 [inline]
 snd_pcm_action+0xe4/0x240 sound/core/pcm_native.c:1388
 __snd_pcm_xrun+0x27f/0x7c0 sound/core/pcm_lib.c:180
 snd_pcm_update_state+0x342/0x430 sound/core/pcm_lib.c:224
 snd_pcm_update_hw_ptr0+0x10b2/0x1b00 sound/core/pcm_lib.c:493
 snd_pcm_update_hw_ptr sound/core/pcm_lib.c:499 [inline]
 __snd_pcm_lib_xfer+0x510/0x1ce0 sound/core/pcm_lib.c:2326
 snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241
 snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630
 snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline]
 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline]
 snd_pcm_oss_write+0xba2/0x11a0 sound/core/oss/pcm_oss.c:2795
 vfs_write+0x284/0xb40 fs/read_write.c:684
 ksys_write+0x14b/0x260 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0e7a70ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe73a3cd48 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0e7a935fa0 RCX: 00007f0e7a70ebe9
RDX: 000000000000fc36 RSI: 0000200000000500 RDI: 0000000000000003
RBP: 00007f0e7a791e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0e7a935fa0 R14: 00007f0e7a935fa0 R15: 0000000000000003
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2)
  2025-08-29 18:38 [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2) syzbot
@ 2025-08-30  0:06 ` syzbot
  2025-09-04 10:20   ` Sebastian Andrzej Siewior
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2025-08-30  0:06 UTC (permalink / raw)
  To: bigeasy, bp, dave.hansen, hpa, linux-kernel, linux-sound, mingo,
	perex, syzkaller-bugs, tglx, tiwai, x86

syzbot has bisected this issue to:

commit d2d6422f8bd17c6bb205133e290625a564194496
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Fri Sep 6 10:59:04 2024 +0000

    x86: Allow to enable PREEMPT_RT.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12db5634580000
start commit:   07d9df80082b Merge tag 'perf-tools-fixes-for-v6.17-2025-08..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=11db5634580000
console output: https://syzkaller.appspot.com/x/log.txt?x=16db5634580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e
dashboard link: https://syzkaller.appspot.com/bug?extid=10b4363fb0f46527f3f3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10307262580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17110242580000

Reported-by: syzbot+10b4363fb0f46527f3f3@syzkaller.appspotmail.com
Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2)
  2025-08-30  0:06 ` syzbot
@ 2025-09-04 10:20   ` Sebastian Andrzej Siewior
  2025-09-04 10:38     ` Takashi Iwai
  0 siblings, 1 reply; 4+ messages in thread
From: Sebastian Andrzej Siewior @ 2025-09-04 10:20 UTC (permalink / raw)
  To: syzbot, tglx
  Cc: bp, dave.hansen, hpa, linux-kernel, linux-sound, mingo, perex,
	syzkaller-bugs, tiwai, x86

On 2025-08-29 17:06:02 [-0700], syzbot wrote:
> syzbot has bisected this issue to:
> 
> commit d2d6422f8bd17c6bb205133e290625a564194496
> Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Date:   Fri Sep 6 10:59:04 2024 +0000
> 
>     x86: Allow to enable PREEMPT_RT.
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12db5634580000
> start commit:   07d9df80082b Merge tag 'perf-tools-fixes-for-v6.17-2025-08..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=11db5634580000
> console output: https://syzkaller.appspot.com/x/log.txt?x=16db5634580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e
> dashboard link: https://syzkaller.appspot.com/bug?extid=10b4363fb0f46527f3f3
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10307262580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17110242580000
> 
> Reported-by: syzbot+10b4363fb0f46527f3f3@syzkaller.appspotmail.com
> Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.")

This is unfortunate. There is nothing that sound did wrong, it is rather
special softirq handling in this case. We don't see this often because
it requires that a timer is cancelled at the time it is running.
The assumption made by sound is that spin_lock_irq() also disables
softirqs. This is not the case on PREEMPT_RT.

The hunk below avoids the splat. Adding local_bh_disable() to
spin_lock_irq() would cure it, too. It would also result in random
synchronisation points across the kernel leading to something less
usable.
The imho best solution would to get rid of softirq_ctrl.lock which has
been proposed
	https://lore.kernel.org/all/20250901163811.963326-4-bigeasy@linutronix.de/

Comments?

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -84,19 +84,24 @@ void snd_pcm_group_init(struct snd_pcm_group *group)
 }
 
 /* define group lock helpers */
-#define DEFINE_PCM_GROUP_LOCK(action, mutex_action) \
+#define DEFINE_PCM_GROUP_LOCK(action, bh_lock, bh_unlock, mutex_action) \
 static void snd_pcm_group_ ## action(struct snd_pcm_group *group, bool nonatomic) \
 { \
-	if (nonatomic) \
+	if (nonatomic) { \
 		mutex_ ## mutex_action(&group->mutex); \
-	else \
-		spin_ ## action(&group->lock); \
+	} else { \
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) && bh_lock)	\
+			local_bh_disable();			\
+		spin_ ## action(&group->lock);			\
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) && bh_unlock)	\
+			local_bh_enable();			\
+	}							\
 }
 
-DEFINE_PCM_GROUP_LOCK(lock, lock);
-DEFINE_PCM_GROUP_LOCK(unlock, unlock);
-DEFINE_PCM_GROUP_LOCK(lock_irq, lock);
-DEFINE_PCM_GROUP_LOCK(unlock_irq, unlock);
+DEFINE_PCM_GROUP_LOCK(lock, 0, 0, lock);
+DEFINE_PCM_GROUP_LOCK(unlock, 0, 0, unlock);
+DEFINE_PCM_GROUP_LOCK(lock_irq, 1, 0, lock);
+DEFINE_PCM_GROUP_LOCK(unlock_irq, 0, 1, unlock);
 
 /**
  * snd_pcm_stream_lock - Lock the PCM stream


Sebastian

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2)
  2025-09-04 10:20   ` Sebastian Andrzej Siewior
@ 2025-09-04 10:38     ` Takashi Iwai
  0 siblings, 0 replies; 4+ messages in thread
From: Takashi Iwai @ 2025-09-04 10:38 UTC (permalink / raw)
  To: Sebastian Andrzej Siewior
  Cc: syzbot, tglx, bp, dave.hansen, hpa, linux-kernel, linux-sound,
	mingo, perex, syzkaller-bugs, tiwai, x86

On Thu, 04 Sep 2025 12:20:56 +0200,
Sebastian Andrzej Siewior wrote:
> 
> On 2025-08-29 17:06:02 [-0700], syzbot wrote:
> > syzbot has bisected this issue to:
> > 
> > commit d2d6422f8bd17c6bb205133e290625a564194496
> > Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> > Date:   Fri Sep 6 10:59:04 2024 +0000
> > 
> >     x86: Allow to enable PREEMPT_RT.
> > 
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12db5634580000
> > start commit:   07d9df80082b Merge tag 'perf-tools-fixes-for-v6.17-2025-08..
> > git tree:       upstream
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=11db5634580000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=16db5634580000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e
> > dashboard link: https://syzkaller.appspot.com/bug?extid=10b4363fb0f46527f3f3
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10307262580000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17110242580000
> > 
> > Reported-by: syzbot+10b4363fb0f46527f3f3@syzkaller.appspotmail.com
> > Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.")
> 
> This is unfortunate. There is nothing that sound did wrong, it is rather
> special softirq handling in this case. We don't see this often because
> it requires that a timer is cancelled at the time it is running.
> The assumption made by sound is that spin_lock_irq() also disables
> softirqs. This is not the case on PREEMPT_RT.
> 
> The hunk below avoids the splat. Adding local_bh_disable() to
> spin_lock_irq() would cure it, too. It would also result in random
> synchronisation points across the kernel leading to something less
> usable.
> The imho best solution would to get rid of softirq_ctrl.lock which has
> been proposed
> 	https://lore.kernel.org/all/20250901163811.963326-4-bigeasy@linutronix.de/
> 
> Comments?

Thank you for the detailed analysis!  It enlightened me.

It'd be appreciated if this gets fixed in the softirq core side.
If nothing else flies, we can take your workaround, sure...


Takashi

> 
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -84,19 +84,24 @@ void snd_pcm_group_init(struct snd_pcm_group *group)
>  }
>  
>  /* define group lock helpers */
> -#define DEFINE_PCM_GROUP_LOCK(action, mutex_action) \
> +#define DEFINE_PCM_GROUP_LOCK(action, bh_lock, bh_unlock, mutex_action) \
>  static void snd_pcm_group_ ## action(struct snd_pcm_group *group, bool nonatomic) \
>  { \
> -	if (nonatomic) \
> +	if (nonatomic) { \
>  		mutex_ ## mutex_action(&group->mutex); \
> -	else \
> -		spin_ ## action(&group->lock); \
> +	} else { \
> +		if (IS_ENABLED(CONFIG_PREEMPT_RT) && bh_lock)	\
> +			local_bh_disable();			\
> +		spin_ ## action(&group->lock);			\
> +		if (IS_ENABLED(CONFIG_PREEMPT_RT) && bh_unlock)	\
> +			local_bh_enable();			\
> +	}							\
>  }
>  
> -DEFINE_PCM_GROUP_LOCK(lock, lock);
> -DEFINE_PCM_GROUP_LOCK(unlock, unlock);
> -DEFINE_PCM_GROUP_LOCK(lock_irq, lock);
> -DEFINE_PCM_GROUP_LOCK(unlock_irq, unlock);
> +DEFINE_PCM_GROUP_LOCK(lock, 0, 0, lock);
> +DEFINE_PCM_GROUP_LOCK(unlock, 0, 0, unlock);
> +DEFINE_PCM_GROUP_LOCK(lock_irq, 1, 0, lock);
> +DEFINE_PCM_GROUP_LOCK(unlock_irq, 0, 1, unlock);
>  
>  /**
>   * snd_pcm_stream_lock - Lock the PCM stream
> 
> 
> Sebastian

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2025-09-04 10:38 UTC | newest]

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2025-08-29 18:38 [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2) syzbot
2025-08-30  0:06 ` syzbot
2025-09-04 10:20   ` Sebastian Andrzej Siewior
2025-09-04 10:38     ` Takashi Iwai

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