[syzbot] [sound?] possible deadlock in snd_timer_close_locked (2)

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Apr 14, 2024, 12:05:22 AMApr 14
to linux-...@vger.kernel.org, linux...@vger.kernel.org, pe...@perex.cz, syzkall...@googlegroups.com, ti...@suse.com, ti...@suse.de
Hello,

syzbot found the following issue on:

HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15fa3f8d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=19df3985ca9ea18a8fdf
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=170d5d29180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e19bd3180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/72ab73815344/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d6d6b0d7071/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/48e275e5478b/bzImage-fe46a7dd.xz

The issue was bisected to:

commit beb45974dd49068b24788bbfc2abe20d50503761
Author: Takashi Iwai <ti...@suse.de>
Date: Tue Feb 27 08:52:45 2024 +0000

ALSA: timer: Use guard() for locking

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1505004d180000
final oops: https://syzkaller.appspot.com/x/report.txt?x=1705004d180000
console output: https://syzkaller.appspot.com/x/log.txt?x=1305004d180000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+19df39...@syzkaller.appspotmail.com
Fixes: beb45974dd49 ("ALSA: timer: Use guard() for locking")

========================================================
WARNING: possible irq lock inversion dependency detected
6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted
--------------------------------------------------------
syz-executor641/5063 just changed the state of lock:
ffff888029a72948 (&timer->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff888029a72948 (&timer->lock){+.+.}-{2:2}, at: class_spinlock_constructor include/linux/spinlock.h:561 [inline]
ffff888029a72948 (&timer->lock){+.+.}-{2:2}, at: snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412
but this lock was taken by another, SOFTIRQ-safe lock in the past:
(&group->lock#2){..-.}-{2:2}


and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&timer->lock);
local_irq_disable();
lock(&group->lock#2);
lock(&timer->lock);
<Interrupt>
lock(&group->lock#2);

*** DEADLOCK ***

3 locks held by syz-executor641/5063:
#0: ffffffff8f2d3228 (register_mutex#4){+.+.}-{3:3}, at: odev_release+0x4e/0x80 sound/core/seq/oss/seq_oss.c:143
#1: ffff88801a37ad78 (&q->timer_mutex){+.+.}-{3:3}, at: queue_delete sound/core/seq/seq_queue.c:124 [inline]
#1: ffff88801a37ad78 (&q->timer_mutex){+.+.}-{3:3}, at: snd_seq_queue_delete+0x5b/0xf0 sound/core/seq/seq_queue.c:188
#2: ffffffff8f2c1a68 (register_mutex){+.+.}-{3:3}, at: class_mutex_constructor include/linux/mutex.h:169 [inline]
#2: ffffffff8f2c1a68 (register_mutex){+.+.}-{3:3}, at: snd_timer_close+0xa3/0x130 sound/core/timer.c:463

the shortest dependencies between 2nd lock and 1st lock:
-> (&group->lock#2){..-.}-{2:2} {
IN-SOFTIRQ-W at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline]
snd_pcm_period_elapsed+0x21/0x50 sound/core/pcm_lib.c:1904
dummy_hrtimer_callback+0x7f/0x180 sound/drivers/dummy.c:385
__run_hrtimer kernel/time/hrtimer.c:1692 [inline]
__hrtimer_run_queues+0x595/0xd00 kernel/time/hrtimer.c:1756
hrtimer_run_softirq+0x19a/0x2c0 kernel/time/hrtimer.c:1773
__do_softirq+0x2bc/0x943 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:707
cpuidle_enter_state+0x118/0x490 drivers/cpuidle/cpuidle.c:267
cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:236 [inline]
do_idle+0x375/0x5d0 kernel/sched/idle.c:332
cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:430
rest_init+0x2e0/0x300 init/main.c:730
arch_call_rest_init+0xe/0x10 init/main.c:831
start_kernel+0x47a/0x500 init/main.c:1077
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:509
x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:490
common_startup_64+0x13e/0x147
INITIAL USE at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:376 [inline]
snd_pcm_group_lock_irq sound/core/pcm_native.c:97 [inline]
snd_pcm_stream_lock_irq sound/core/pcm_native.c:136 [inline]
class_pcm_stream_lock_irq_constructor include/sound/pcm.h:666 [inline]
snd_pcm_hw_params+0x201/0x1ea0 sound/core/pcm_native.c:740
snd_pcm_oss_change_params_locked+0x20d5/0x3e00 sound/core/oss/pcm_oss.c:965
snd_pcm_oss_make_ready_locked sound/core/oss/pcm_oss.c:1187 [inline]
snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1515 [inline]
snd_pcm_oss_read+0x24c/0x940 sound/core/oss/pcm_oss.c:2773
do_loop_readv_writev fs/read_write.c:761 [inline]
vfs_readv+0x68f/0xa50 fs/read_write.c:934
do_readv+0x1b1/0x350 fs/read_write.c:994
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
}
... key at: [<ffffffff9485f200>] snd_pcm_group_init.__key+0x0/0x20
... acquired at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
class_spinlock_irqsave_constructor include/linux/spinlock.h:574 [inline]
snd_timer_notify+0x103/0x3d0 sound/core/timer.c:1040
snd_pcm_action sound/core/pcm_native.c:1370 [inline]
snd_pcm_start+0x3fa/0x4c0 sound/core/pcm_native.c:1478
__snd_pcm_lib_xfer+0x1af3/0x1e30 sound/core/pcm_lib.c:2301
snd_pcm_oss_read3+0x3ea/0x600 sound/core/oss/pcm_oss.c:1281
snd_pcm_plug_read_transfer+0x3a1/0x470 sound/core/oss/pcm_plugin.c:663
snd_pcm_oss_read2+0x296/0x430 sound/core/oss/pcm_oss.c:1482
snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1520 [inline]
snd_pcm_oss_read+0x45b/0x940 sound/core/oss/pcm_oss.c:2773
do_loop_readv_writev fs/read_write.c:761 [inline]
vfs_readv+0x68f/0xa50 fs/read_write.c:934
do_readv+0x1b1/0x350 fs/read_write.c:994
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

-> (&timer->lock){+.+.}-{2:2} {
HARDIRQ-ON-W at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
class_spinlock_constructor include/linux/spinlock.h:561 [inline]
snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412
snd_timer_close+0xae/0x130 sound/core/timer.c:464
snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302
queue_delete sound/core/seq/seq_queue.c:126 [inline]
snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188
delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline]
snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416
odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144
__fput+0x429/0x8a0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa1b/0x27e0 kernel/exit.c:878
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
SOFTIRQ-ON-W at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
class_spinlock_constructor include/linux/spinlock.h:561 [inline]
snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412
snd_timer_close+0xae/0x130 sound/core/timer.c:464
snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302
queue_delete sound/core/seq/seq_queue.c:126 [inline]
snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188
delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline]
snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416
odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144
__fput+0x429/0x8a0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa1b/0x27e0 kernel/exit.c:878
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
INITIAL USE at:
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
class_spinlock_irqsave_constructor include/linux/spinlock.h:574 [inline]
snd_timer_notify+0x103/0x3d0 sound/core/timer.c:1040
snd_pcm_action sound/core/pcm_native.c:1370 [inline]
snd_pcm_start+0x3fa/0x4c0 sound/core/pcm_native.c:1478
__snd_pcm_lib_xfer+0x1af3/0x1e30 sound/core/pcm_lib.c:2301
snd_pcm_oss_read3+0x3ea/0x600 sound/core/oss/pcm_oss.c:1281
snd_pcm_plug_read_transfer+0x3a1/0x470 sound/core/oss/pcm_plugin.c:663
snd_pcm_oss_read2+0x296/0x430 sound/core/oss/pcm_oss.c:1482
snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1520 [inline]
snd_pcm_oss_read+0x45b/0x940 sound/core/oss/pcm_oss.c:2773
do_loop_readv_writev fs/read_write.c:761 [inline]
vfs_readv+0x68f/0xa50 fs/read_write.c:934
do_readv+0x1b1/0x350 fs/read_write.c:994
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
}
... key at: [<ffffffff9485efe0>] snd_timer_new.__key+0x0/0x20
... acquired at:
mark_lock+0x223/0x350 kernel/locking/lockdep.c:4678
__lock_acquire+0x116e/0x1fd0 kernel/locking/lockdep.c:5091
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
class_spinlock_constructor include/linux/spinlock.h:561 [inline]
snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412
snd_timer_close+0xae/0x130 sound/core/timer.c:464
snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302
queue_delete sound/core/seq/seq_queue.c:126 [inline]
snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188
delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline]
snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416
odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144
__fput+0x429/0x8a0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa1b/0x27e0 kernel/exit.c:878
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75


stack backtrace:
CPU: 0 PID: 5063 Comm: syz-executor641 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
mark_lock_irq+0x867/0xc20 kernel/locking/lockdep.c:4236
mark_lock+0x223/0x350 kernel/locking/lockdep.c:4678
__lock_acquire+0x116e/0x1fd0 kernel/locking/lockdep.c:5091
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
class_spinlock_constructor include/linux/spinlock.h:561 [inline]
snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412
snd_timer_close+0xae/0x130 sound/core/timer.c:464
snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302
queue_delete sound/core/seq/seq_queue.c:126 [inline]
snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188
delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline]
snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416
odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144
__fput+0x429/0x8a0 fs/file_table.c:422
task_work_run+0x24f/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa1b/0x27e0 kernel/exit.c:878
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f4d2af16c79
Code: Unable to access opcode bytes at 0x7f4d2af16c4f.
RSP: 002b:00007ffd402f0ee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda


---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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#syz undup

Takashi Iwai

unread,
Apr 18, 2024, 3:37:36 AM (12 days ago) Apr 18
to syzbot, linux-...@vger.kernel.org, linux...@vger.kernel.org, pe...@perex.cz, syzkall...@googlegroups.com, ti...@suse.com, ti...@suse.de
#syz fix: ALSA: timer: Fix missing irq-disable at closing
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