syzbot

=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
5.9.0-syzkaller #0 Not tainted
-----------------------------------------------------
syz-executor.0/9536 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff888099088760 (&card->ctl_files_rwlock){.+.+}-{2:2}, at: snd_ctl_notify+0x86/0x550 sound/core/control.c:153

and this task is already holding:
ffff888214d91908 (&group->lock){..-.}-{2:2}, at: __snd_pcm_lib_xfer+0xb6d/0x12f0 sound/core/pcm_lib.c:2227
which would create a new lock dependency:
 (&group->lock){..-.}-{2:2} -> (&card->ctl_files_rwlock){.+.+}-{2:2}

but this new dependency connects a SOFTIRQ-irq-safe lock:
 (&group->lock){..-.}-{2:2}

... which became SOFTIRQ-irq-safe at:
  lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0xaa/0xd0 kernel/locking/spinlock.c:159
  snd_pcm_period_elapsed+0x2c/0x210 sound/core/pcm_lib.c:1799
  call_timer_fn+0x91/0x160 kernel/time/timer.c:1415
  expire_timers kernel/time/timer.c:1460 [inline]
  __run_timers+0x770/0x9a0 kernel/time/timer.c:1757
  run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1770
  __do_softirq+0x388/0x748 kernel/softirq.c:298
  asm_call_irq_on_stack+0xf/0x20
  __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
  run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
  do_softirq_own_stack+0x9a/0xe0 arch/x86/kernel/irq_64.c:77
  invoke_softirq kernel/softirq.c:393 [inline]
  __irq_exit_rcu+0x200/0x230 kernel/softirq.c:423
  irq_exit_rcu+0x5/0x20 kernel/softirq.c:435
  sysvec_apic_timer_interrupt+0xe0/0xf0 arch/x86/kernel/apic/apic.c:1091
  asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
  arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline]
  seqcount_lockdep_reader_access+0x15b/0x180 include/linux/seqlock.h:105
  ktime_get_ts64+0x55/0x300 kernel/time/timekeeping.c:964
  posix_get_monotonic_timespec+0x36/0x1b0 kernel/time/posix-timers.c:199
  __do_sys_clock_gettime kernel/time/posix-timers.c:1092 [inline]
  __se_sys_clock_gettime kernel/time/posix-timers.c:1082 [inline]
  __x64_sys_clock_gettime+0x169/0x1f0 kernel/time/posix-timers.c:1082
  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

to a SOFTIRQ-irq-unsafe lock:
 (&card->ctl_files_rwlock){.+.+}-{2:2}

... which became SOFTIRQ-irq-unsafe at:
...
  lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
  __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
  _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
  snd_ctl_notify+0x86/0x550 sound/core/control.c:153
  __snd_ctl_add_replace+0x582/0x8a0 sound/core/control.c:382
  snd_ctl_add_replace sound/core/control.c:399 [inline]
  snd_ctl_add+0x6e/0x110 sound/core/control.c:426
  snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline]
  snd_dummy_probe+0x12bb/0x1ff0 sound/drivers/dummy.c:1080
  platform_drv_probe+0xcd/0x150 drivers/base/platform.c:761
  really_probe+0x74b/0x1100 drivers/base/dd.c:558
  driver_probe_device+0x106/0x1a0 drivers/base/dd.c:738
  bus_for_each_drv+0x108/0x170 drivers/base/bus.c:431
  __device_attach+0x262/0x3f0 drivers/base/dd.c:912
  bus_probe_device+0xb8/0x1f0 drivers/base/bus.c:491
  device_add+0x15e6/0x1960 drivers/base/core.c:2936
  platform_device_add+0x4ad/0x6e0 drivers/base/platform.c:611
  platform_device_register_full+0x445/0x530 drivers/base/platform.c:734
  platform_device_register_resndata include/linux/platform_device.h:131 [inline]
  platform_device_register_simple include/linux/platform_device.h:160 [inline]
  alsa_card_dummy_init+0x1b3/0x39c sound/drivers/dummy.c:1168
  do_one_initcall+0x14b/0x350 init/main.c:1205
  do_initcall_level+0x1fb/0x2c0 init/main.c:1278
  do_initcalls+0x4b/0x8c init/main.c:1294
  kernel_init_freeable+0x356/0x474 init/main.c:1514
  kernel_init+0xd/0x290 init/main.c:1403
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

other info that might help us debug this:

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&card->ctl_files_rwlock);
                               local_irq_disable();
                               lock(&group->lock);
                               lock(&card->ctl_files_rwlock);
  <Interrupt>
    lock(&group->lock);

 *** DEADLOCK ***

1 lock held by syz-executor.0/9536:
 #0: ffff888214d91908 (&group->lock){..-.}-{2:2}, at: __snd_pcm_lib_xfer+0xb6d/0x12f0 sound/core/pcm_lib.c:2227

the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (&group->lock){..-.}-{2:2} {
   IN-SOFTIRQ-W at:
                    lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
                    __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                    _raw_spin_lock_irqsave+0xaa/0xd0 kernel/locking/spinlock.c:159
                    snd_pcm_period_elapsed+0x2c/0x210 sound/core/pcm_lib.c:1799
                    call_timer_fn+0x91/0x160 kernel/time/timer.c:1415
                    expire_timers kernel/time/timer.c:1460 [inline]
                    __run_timers+0x770/0x9a0 kernel/time/timer.c:1757
                    run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1770
                    __do_softirq+0x388/0x748 kernel/softirq.c:298
                    asm_call_irq_on_stack+0xf/0x20
                    __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
                    run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
                    do_softirq_own_stack+0x9a/0xe0 arch/x86/kernel/irq_64.c:77
                    invoke_softirq kernel/softirq.c:393 [inline]
                    __irq_exit_rcu+0x200/0x230 kernel/softirq.c:423
                    irq_exit_rcu+0x5/0x20 kernel/softirq.c:435
                    sysvec_apic_timer_interrupt+0xe0/0xf0 arch/x86/kernel/apic/apic.c:1091
                    asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
                    arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline]
                    seqcount_lockdep_reader_access+0x15b/0x180 include/linux/seqlock.h:105
                    ktime_get_ts64+0x55/0x300 kernel/time/timekeeping.c:964
                    posix_get_monotonic_timespec+0x36/0x1b0 kernel/time/posix-timers.c:199
                    __do_sys_clock_gettime kernel/time/posix-timers.c:1092 [inline]
                    __se_sys_clock_gettime kernel/time/posix-timers.c:1082 [inline]
                    __x64_sys_clock_gettime+0x169/0x1f0 kernel/time/posix-timers.c:1082
                    do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                    entry_SYSCALL_64_after_hwframe+0x44/0xa9
   INITIAL USE at:
                   lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
                   __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
                   _raw_spin_lock_irq+0xa6/0xc0 kernel/locking/spinlock.c:167
                   spin_lock_irq include/linux/spinlock.h:379 [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]
                   snd_pcm_hw_params+0xca/0x16a0 sound/core/pcm_native.c:672
                   snd_pcm_oss_change_params_locked+0x2102/0x3e00 sound/core/oss/pcm_oss.c:941
                   snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1084 [inline]
                   snd_pcm_oss_get_active_substream+0x1ca/0x280 sound/core/oss/pcm_oss.c:1101
                   snd_pcm_oss_get_formats+0x34/0x360 sound/core/oss/pcm_oss.c:1817
                   snd_pcm_oss_set_format sound/core/oss/pcm_oss.c:1858 [inline]
                   snd_pcm_oss_ioctl+0x9ee/0x4630 sound/core/oss/pcm_oss.c:2617
                   vfs_ioctl fs/ioctl.c:48 [inline]
                   __do_sys_ioctl fs/ioctl.c:753 [inline]
                   __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
                   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
                   entry_SYSCALL_64_after_hwframe+0x44/0xa9
 }
 ... key      at: [<ffffffff8e64f820>] snd_pcm_group_init.__key+0x0/0x40
 ... acquired at:
   lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
   snd_ctl_notify+0x86/0x550 sound/core/control.c:153
   loopback_check_format sound/drivers/aloop.c:353 [inline]
   loopback_trigger+0xd10/0x17f0 sound/drivers/aloop.c:387
   snd_pcm_do_start sound/core/pcm_native.c:1350 [inline]
   snd_pcm_action_single sound/core/pcm_native.c:1207 [inline]
   snd_pcm_action sound/core/pcm_native.c:1290 [inline]
   snd_pcm_start+0x475/0x6d0 sound/core/pcm_native.c:1391
   __snd_pcm_lib_xfer+0xf3d/0x12f0 sound/core/pcm_lib.c:2247
   snd_pcm_oss_write3+0x209/0x330 sound/core/oss/pcm_oss.c:1221
   snd_pcm_oss_write2+0x1bb/0x370 sound/core/oss/pcm_oss.c:1361
   snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1419 [inline]
   snd_pcm_oss_write+0x911/0xd70 sound/core/oss/pcm_oss.c:2765
   vfs_write+0x2dd/0xd10 fs/read_write.c:584
   ksys_write+0x11b/0x220 fs/read_write.c:639
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9


the dependencies between the lock to be acquired
 and SOFTIRQ-irq-unsafe lock:
-> (&card->ctl_files_rwlock){.+.+}-{2:2} {
   HARDIRQ-ON-R at:
                    lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
                    __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                    _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
                    snd_ctl_notify+0x86/0x550 sound/core/control.c:153
                    __snd_ctl_add_replace+0x582/0x8a0 sound/core/control.c:382
                    snd_ctl_add_replace sound/core/control.c:399 [inline]
                    snd_ctl_add+0x6e/0x110 sound/core/control.c:426
                    snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline]
                    snd_dummy_probe+0x12bb/0x1ff0 sound/drivers/dummy.c:1080
                    platform_drv_probe+0xcd/0x150 drivers/base/platform.c:761
                    really_probe+0x74b/0x1100 drivers/base/dd.c:558
                    driver_probe_device+0x106/0x1a0 drivers/base/dd.c:738
                    bus_for_each_drv+0x108/0x170 drivers/base/bus.c:431
                    __device_attach+0x262/0x3f0 drivers/base/dd.c:912
                    bus_probe_device+0xb8/0x1f0 drivers/base/bus.c:491
                    device_add+0x15e6/0x1960 drivers/base/core.c:2936
                    platform_device_add+0x4ad/0x6e0 drivers/base/platform.c:611
                    platform_device_register_full+0x445/0x530 drivers/base/platform.c:734
                    platform_device_register_resndata include/linux/platform_device.h:131 [inline]
                    platform_device_register_simple include/linux/platform_device.h:160 [inline]
                    alsa_card_dummy_init+0x1b3/0x39c sound/drivers/dummy.c:1168
                    do_one_initcall+0x14b/0x350 init/main.c:1205
                    do_initcall_level+0x1fb/0x2c0 init/main.c:1278
                    do_initcalls+0x4b/0x8c init/main.c:1294
                    kernel_init_freeable+0x356/0x474 init/main.c:1514
                    kernel_init+0xd/0x290 init/main.c:1403
                    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
   SOFTIRQ-ON-R at:
                    lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
                    __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                    _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
                    snd_ctl_notify+0x86/0x550 sound/core/control.c:153
                    __snd_ctl_add_replace+0x582/0x8a0 sound/core/control.c:382
                    snd_ctl_add_replace sound/core/control.c:399 [inline]
                    snd_ctl_add+0x6e/0x110 sound/core/control.c:426
                    snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline]
                    snd_dummy_probe+0x12bb/0x1ff0 sound/drivers/dummy.c:1080
                    platform_drv_probe+0xcd/0x150 drivers/base/platform.c:761
                    really_probe+0x74b/0x1100 drivers/base/dd.c:558
                    driver_probe_device+0x106/0x1a0 drivers/base/dd.c:738
                    bus_for_each_drv+0x108/0x170 drivers/base/bus.c:431
                    __device_attach+0x262/0x3f0 drivers/base/dd.c:912
                    bus_probe_device+0xb8/0x1f0 drivers/base/bus.c:491
                    device_add+0x15e6/0x1960 drivers/base/core.c:2936
                    platform_device_add+0x4ad/0x6e0 drivers/base/platform.c:611
                    platform_device_register_full+0x445/0x530 drivers/base/platform.c:734
                    platform_device_register_resndata include/linux/platform_device.h:131 [inline]
                    platform_device_register_simple include/linux/platform_device.h:160 [inline]
                    alsa_card_dummy_init+0x1b3/0x39c sound/drivers/dummy.c:1168
                    do_one_initcall+0x14b/0x350 init/main.c:1205
                    do_initcall_level+0x1fb/0x2c0 init/main.c:1278
                    do_initcalls+0x4b/0x8c init/main.c:1294
                    kernel_init_freeable+0x356/0x474 init/main.c:1514
                    kernel_init+0xd/0x290 init/main.c:1403
                    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
   INITIAL READ USE at:
                        lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
                        __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
                        _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
                        snd_ctl_notify+0x86/0x550 sound/core/control.c:153
                        __snd_ctl_add_replace+0x582/0x8a0 sound/core/control.c:382
                        snd_ctl_add_replace sound/core/control.c:399 [inline]
                        snd_ctl_add+0x6e/0x110 sound/core/control.c:426
                        snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline]
                        snd_dummy_probe+0x12bb/0x1ff0 sound/drivers/dummy.c:1080
                        platform_drv_probe+0xcd/0x150 drivers/base/platform.c:761
                        really_probe+0x74b/0x1100 drivers/base/dd.c:558
                        driver_probe_device+0x106/0x1a0 drivers/base/dd.c:738
                        bus_for_each_drv+0x108/0x170 drivers/base/bus.c:431
                        __device_attach+0x262/0x3f0 drivers/base/dd.c:912
                        bus_probe_device+0xb8/0x1f0 drivers/base/bus.c:491
                        device_add+0x15e6/0x1960 drivers/base/core.c:2936
                        platform_device_add+0x4ad/0x6e0 drivers/base/platform.c:611
                        platform_device_register_full+0x445/0x530 drivers/base/platform.c:734
                        platform_device_register_resndata include/linux/platform_device.h:131 [inline]
                        platform_device_register_simple include/linux/platform_device.h:160 [inline]
                        alsa_card_dummy_init+0x1b3/0x39c sound/drivers/dummy.c:1168
                        do_one_initcall+0x14b/0x350 init/main.c:1205
                        do_initcall_level+0x1fb/0x2c0 init/main.c:1278
                        do_initcalls+0x4b/0x8c init/main.c:1294
                        kernel_init_freeable+0x356/0x474 init/main.c:1514
                        kernel_init+0xd/0x290 init/main.c:1403
                        ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
 }
 ... key      at: [<ffffffff8e64d6a0>] snd_card_new.__key.3+0x0/0x40
 ... acquired at:
   lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
   __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
   _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
   snd_ctl_notify+0x86/0x550 sound/core/control.c:153
   loopback_check_format sound/drivers/aloop.c:353 [inline]
   loopback_trigger+0xd10/0x17f0 sound/drivers/aloop.c:387
   snd_pcm_do_start sound/core/pcm_native.c:1350 [inline]
   snd_pcm_action_single sound/core/pcm_native.c:1207 [inline]
   snd_pcm_action sound/core/pcm_native.c:1290 [inline]
   snd_pcm_start+0x475/0x6d0 sound/core/pcm_native.c:1391
   __snd_pcm_lib_xfer+0xf3d/0x12f0 sound/core/pcm_lib.c:2247
   snd_pcm_oss_write3+0x209/0x330 sound/core/oss/pcm_oss.c:1221
   snd_pcm_oss_write2+0x1bb/0x370 sound/core/oss/pcm_oss.c:1361
   snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1419 [inline]
   snd_pcm_oss_write+0x911/0xd70 sound/core/oss/pcm_oss.c:2765
   vfs_write+0x2dd/0xd10 fs/read_write.c:584
   ksys_write+0x11b/0x220 fs/read_write.c:639
   do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
   entry_SYSCALL_64_after_hwframe+0x44/0xa9


stack backtrace:
CPU: 0 PID: 9536 Comm: syz-executor.0 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d6/0x29e lib/dump_stack.c:118
 print_bad_irq_dependency kernel/locking/lockdep.c:2450 [inline]
 check_irq_usage kernel/locking/lockdep.c:2679 [inline]
 check_prev_add+0x3466/0x4f90 kernel/locking/lockdep.c:2868
 check_prevs_add kernel/locking/lockdep.c:2989 [inline]
 validate_chain kernel/locking/lockdep.c:3607 [inline]
 __lock_acquire+0x485d/0x6a40 kernel/locking/lockdep.c:4837
 lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442
 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
 _raw_read_lock+0x32/0x40 kernel/locking/spinlock.c:223
 snd_ctl_notify+0x86/0x550 sound/core/control.c:153
 loopback_check_format sound/drivers/aloop.c:353 [inline]
 loopback_trigger+0xd10/0x17f0 sound/drivers/aloop.c:387
 snd_pcm_do_start sound/core/pcm_native.c:1350 [inline]
 snd_pcm_action_single sound/core/pcm_native.c:1207 [inline]
 snd_pcm_action sound/core/pcm_native.c:1290 [inline]
 snd_pcm_start+0x475/0x6d0 sound/core/pcm_native.c:1391
 __snd_pcm_lib_xfer+0xf3d/0x12f0 sound/core/pcm_lib.c:2247
 snd_pcm_oss_write3+0x209/0x330 sound/core/oss/pcm_oss.c:1221
 snd_pcm_oss_write2+0x1bb/0x370 sound/core/oss/pcm_oss.c:1361
 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1419 [inline]
 snd_pcm_oss_write+0x911/0xd70 sound/core/oss/pcm_oss.c:2765
 vfs_write+0x2dd/0xd10 fs/read_write.c:584
 ksys_write+0x11b/0x220 fs/read_write.c:639
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de59
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2ceabb4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000003a840 RCX: 000000000045de59
RDX: 0000000020000318 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000118c008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bfd4
R13: 00007ffff6ced0cf R14: 00007f2ceabb59c0 R15: 000000000118bfd4