===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.9.0-rc5-next-20200915-syzkaller #0 Not tainted ----------------------------------------------------- syz-executor.1/16822 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffff888099e30760 (&card->ctl_files_rwlock){.+.+}-{2:2}, at: snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 and this task is already holding: ffff888214e4b908 (&group->lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:379 [inline] ffff888214e4b908 (&group->lock){..-.}-{2:2}, at: snd_pcm_group_lock_irq sound/core/pcm_native.c:97 [inline] ffff888214e4b908 (&group->lock){..-.}-{2:2}, at: snd_pcm_stream_lock_irq+0x8e/0xb0 sound/core/pcm_native.c:136 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+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159 _snd_pcm_stream_lock_irqsave+0x9f/0xd0 sound/core/pcm_native.c:170 snd_pcm_period_elapsed+0x24/0x250 sound/core/pcm_lib.c:1799 loopback_jiffies_timer_function+0x1a8/0x220 sound/drivers/aloop.c:669 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x202/0xa42 kernel/softirq.c:298 run_ksoftirqd kernel/softirq.c:652 [inline] run_ksoftirqd+0xcf/0x170 kernel/softirq.c:644 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 to a SOFTIRQ-irq-unsafe lock: (&card->ctl_files_rwlock){.+.+}-{2:2} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223 snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 snd_ctl_notify+0x8f/0xb0 sound/core/control.c:181 __snd_ctl_add_replace+0x638/0x800 sound/core/control.c:382 snd_ctl_add_replace+0x76/0x130 sound/core/control.c:399 snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline] snd_dummy_probe+0xbbf/0x1050 sound/drivers/dummy.c:1080 platform_drv_probe+0x87/0x140 drivers/base/platform.c:761 really_probe+0x282/0x9f0 drivers/base/dd.c:553 driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:737 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:843 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x470 drivers/base/dd.c:911 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb17/0x1c40 drivers/base/core.c:2926 platform_device_add+0x34f/0x6d0 drivers/base/platform.c:611 platform_device_register_full+0x38c/0x4e0 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+0x1cc/0x2e0 sound/drivers/dummy.c:1168 do_one_initcall+0x103/0x6f0 init/main.c:1204 do_initcall_level init/main.c:1277 [inline] do_initcalls init/main.c:1293 [inline] do_basic_setup init/main.c:1313 [inline] kernel_init_freeable+0x5e9/0x66d init/main.c:1512 kernel_init+0xd/0x1c0 init/main.c:1402 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); lock(&group->lock); *** DEADLOCK *** 1 lock held by syz-executor.1/16822: #0: ffff888214e4b908 (&group->lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:379 [inline] #0: ffff888214e4b908 (&group->lock){..-.}-{2:2}, at: snd_pcm_group_lock_irq sound/core/pcm_native.c:97 [inline] #0: ffff888214e4b908 (&group->lock){..-.}-{2:2}, at: snd_pcm_stream_lock_irq+0x8e/0xb0 sound/core/pcm_native.c:136 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&group->lock){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159 _snd_pcm_stream_lock_irqsave+0x9f/0xd0 sound/core/pcm_native.c:170 snd_pcm_period_elapsed+0x24/0x250 sound/core/pcm_lib.c:1799 loopback_jiffies_timer_function+0x1a8/0x220 sound/drivers/aloop.c:669 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x202/0xa42 kernel/softirq.c:298 run_ksoftirqd kernel/softirq.c:652 [inline] run_ksoftirqd+0xcf/0x170 kernel/softirq.c:644 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 INITIAL USE at: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x94/0xd0 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+0x12a/0x1880 sound/core/pcm_native.c:672 snd_pcm_kernel_ioctl+0xd1/0x240 sound/core/pcm_native.c:3325 snd_pcm_oss_change_params_locked+0x130c/0x3430 sound/core/oss/pcm_oss.c:941 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1084 [inline] snd_pcm_oss_make_ready+0xe6/0x2e0 sound/core/oss/pcm_oss.c:1143 snd_pcm_oss_sync+0x1de/0x800 sound/core/oss/pcm_oss.c:1708 snd_pcm_oss_release+0x276/0x300 sound/core/oss/pcm_oss.c:2546 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:163 [inline] exit_to_user_mode_prepare+0x1e2/0x1f0 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 } ... key at: [] __key.7+0x0/0x40 ... acquired at: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223 snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 snd_ctl_notify+0x8f/0xb0 sound/core/control.c:181 loopback_check_format sound/drivers/aloop.c:358 [inline] loopback_trigger+0x10df/0x1990 sound/drivers/aloop.c:387 snd_pcm_do_start sound/core/pcm_native.c:1350 [inline] snd_pcm_do_start+0xb1/0xf0 sound/core/pcm_native.c:1345 snd_pcm_action_single sound/core/pcm_native.c:1207 [inline] snd_pcm_action+0xc8/0x170 sound/core/pcm_native.c:1290 __snd_pcm_lib_xfer+0x1202/0x1a90 sound/core/pcm_lib.c:2247 snd_pcm_oss_write3+0x107/0x320 sound/core/oss/pcm_oss.c:1221 io_playback_transfer+0x27e/0x330 sound/core/oss/io.c:47 snd_pcm_plug_write_transfer+0x2cd/0x3f0 sound/core/oss/pcm_plugin.c:624 snd_pcm_oss_write2+0x245/0x3f0 sound/core/oss/pcm_oss.c:1353 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1419 [inline] snd_pcm_oss_write+0x705/0x940 sound/core/oss/pcm_oss.c:2765 vfs_write+0x28e/0x700 fs/read_write.c:593 ksys_write+0x12d/0x250 fs/read_write.c:648 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+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223 snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 snd_ctl_notify+0x8f/0xb0 sound/core/control.c:181 __snd_ctl_add_replace+0x638/0x800 sound/core/control.c:382 snd_ctl_add_replace+0x76/0x130 sound/core/control.c:399 snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline] snd_dummy_probe+0xbbf/0x1050 sound/drivers/dummy.c:1080 platform_drv_probe+0x87/0x140 drivers/base/platform.c:761 really_probe+0x282/0x9f0 drivers/base/dd.c:553 driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:737 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:843 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x470 drivers/base/dd.c:911 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb17/0x1c40 drivers/base/core.c:2926 platform_device_add+0x34f/0x6d0 drivers/base/platform.c:611 platform_device_register_full+0x38c/0x4e0 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+0x1cc/0x2e0 sound/drivers/dummy.c:1168 do_one_initcall+0x103/0x6f0 init/main.c:1204 do_initcall_level init/main.c:1277 [inline] do_initcalls init/main.c:1293 [inline] do_basic_setup init/main.c:1313 [inline] kernel_init_freeable+0x5e9/0x66d init/main.c:1512 kernel_init+0xd/0x1c0 init/main.c:1402 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 SOFTIRQ-ON-R at: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223 snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 snd_ctl_notify+0x8f/0xb0 sound/core/control.c:181 __snd_ctl_add_replace+0x638/0x800 sound/core/control.c:382 snd_ctl_add_replace+0x76/0x130 sound/core/control.c:399 snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline] snd_dummy_probe+0xbbf/0x1050 sound/drivers/dummy.c:1080 platform_drv_probe+0x87/0x140 drivers/base/platform.c:761 really_probe+0x282/0x9f0 drivers/base/dd.c:553 driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:737 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:843 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x470 drivers/base/dd.c:911 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb17/0x1c40 drivers/base/core.c:2926 platform_device_add+0x34f/0x6d0 drivers/base/platform.c:611 platform_device_register_full+0x38c/0x4e0 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+0x1cc/0x2e0 sound/drivers/dummy.c:1168 do_one_initcall+0x103/0x6f0 init/main.c:1204 do_initcall_level init/main.c:1277 [inline] do_initcalls init/main.c:1293 [inline] do_basic_setup init/main.c:1313 [inline] kernel_init_freeable+0x5e9/0x66d init/main.c:1512 kernel_init+0xd/0x1c0 init/main.c:1402 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 INITIAL USE at: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223 snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 snd_ctl_notify+0x8f/0xb0 sound/core/control.c:181 __snd_ctl_add_replace+0x638/0x800 sound/core/control.c:382 snd_ctl_add_replace+0x76/0x130 sound/core/control.c:399 snd_card_dummy_new_mixer sound/drivers/dummy.c:885 [inline] snd_dummy_probe+0xbbf/0x1050 sound/drivers/dummy.c:1080 platform_drv_probe+0x87/0x140 drivers/base/platform.c:761 really_probe+0x282/0x9f0 drivers/base/dd.c:553 driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:737 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:843 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x470 drivers/base/dd.c:911 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb17/0x1c40 drivers/base/core.c:2926 platform_device_add+0x34f/0x6d0 drivers/base/platform.c:611 platform_device_register_full+0x38c/0x4e0 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+0x1cc/0x2e0 sound/drivers/dummy.c:1168 do_one_initcall+0x103/0x6f0 init/main.c:1204 do_initcall_level init/main.c:1277 [inline] do_initcalls init/main.c:1293 [inline] do_basic_setup init/main.c:1313 [inline] kernel_init_freeable+0x5e9/0x66d init/main.c:1512 kernel_init+0xd/0x1c0 init/main.c:1402 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 (null) at: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 0 PID: 16822 Comm: syz-executor.1 Not tainted 5.9.0-rc5-next-20200915-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:print_lock_trace kernel/locking/lockdep.c:1751 [inline] RIP: 0010:print_lock_class_header kernel/locking/lockdep.c:2240 [inline] RIP: 0010:print_shortest_lock_dependencies.cold+0x110/0x2af kernel/locking/lockdep.c:2263 Code: 48 8b 04 24 48 c1 e8 03 42 80 3c 20 00 74 09 48 8b 3c 24 e8 b1 21 d9 f9 48 8b 04 24 48 8b 00 48 8d 78 14 48 89 fa 48 c1 ea 03 <42> 0f b6 0c 22 48 89 fa 83 e2 07 83 c2 03 38 ca 7c 08 84 c9 0f 85 RSP: 0018:ffffc9001618f3a0 EFLAGS: 00010003 RAX: 0000000000000001 RBX: ffffc9001618f558 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff815c26a7 RDI: 0000000000000015 RBP: ffffc9001618f558 R08: 0000000000000004 R09: ffff8880ae620f8b R10: 0000000000000000 R11: 6c6c756e28202020 R12: dffffc0000000000 R13: ffffffff8c9ee190 R14: 0000000000000009 R15: 0000000000000000 FS: 00007f046fb00700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000768000 CR3: 0000000098bd5000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: print_bad_irq_dependency kernel/locking/lockdep.c:2402 [inline] check_irq_usage.cold+0x46b/0x5b0 kernel/locking/lockdep.c:2634 check_prev_add kernel/locking/lockdep.c:2823 [inline] check_prevs_add kernel/locking/lockdep.c:2944 [inline] validate_chain kernel/locking/lockdep.c:3562 [inline] __lock_acquire+0x2800/0x55d0 kernel/locking/lockdep.c:4796 lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223 snd_ctl_notify.part.0+0x36/0x550 sound/core/control.c:153 snd_ctl_notify+0x8f/0xb0 sound/core/control.c:181 loopback_check_format sound/drivers/aloop.c:358 [inline] loopback_trigger+0x10df/0x1990 sound/drivers/aloop.c:387 snd_pcm_do_start sound/core/pcm_native.c:1350 [inline] snd_pcm_do_start+0xb1/0xf0 sound/core/pcm_native.c:1345 snd_pcm_action_single sound/core/pcm_native.c:1207 [inline] snd_pcm_action+0xc8/0x170 sound/core/pcm_native.c:1290 __snd_pcm_lib_xfer+0x1202/0x1a90 sound/core/pcm_lib.c:2247 snd_pcm_oss_write3+0x107/0x320 sound/core/oss/pcm_oss.c:1221 io_playback_transfer+0x27e/0x330 sound/core/oss/io.c:47 snd_pcm_plug_write_transfer+0x2cd/0x3f0 sound/core/oss/pcm_plugin.c:624 snd_pcm_oss_write2+0x245/0x3f0 sound/core/oss/pcm_oss.c:1353 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1419 [inline] snd_pcm_oss_write+0x705/0x940 sound/core/oss/pcm_oss.c:2765 vfs_write+0x28e/0x700 fs/read_write.c:593 ksys_write+0x12d/0x250 fs/read_write.c:648 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5f9 Code: 5d 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f046faffc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000039240 RCX: 000000000045d5f9 RDX: 0000000000001000 RSI: 0000000020000300 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd37fb845f R14: 00007f046fb009c0 R15: 000000000118cf4c Modules linked in: ---[ end trace 0c0184b504d09b90 ]--- RIP: 0010:print_lock_trace kernel/locking/lockdep.c:1751 [inline] RIP: 0010:print_lock_class_header kernel/locking/lockdep.c:2240 [inline] RIP: 0010:print_shortest_lock_dependencies.cold+0x110/0x2af kernel/locking/lockdep.c:2263 Code: 48 8b 04 24 48 c1 e8 03 42 80 3c 20 00 74 09 48 8b 3c 24 e8 b1 21 d9 f9 48 8b 04 24 48 8b 00 48 8d 78 14 48 89 fa 48 c1 ea 03 <42> 0f b6 0c 22 48 89 fa 83 e2 07 83 c2 03 38 ca 7c 08 84 c9 0f 85 RSP: 0018:ffffc9001618f3a0 EFLAGS: 00010003 RAX: 0000000000000001 RBX: ffffc9001618f558 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff815c26a7 RDI: 0000000000000015 RBP: ffffc9001618f558 R08: 0000000000000004 R09: ffff8880ae620f8b R10: 0000000000000000 R11: 6c6c756e28202020 R12: dffffc0000000000 R13: ffffffff8c9ee190 R14: 0000000000000009 R15: 0000000000000000 FS: 00007f046fb00700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000768000 CR3: 0000000098bd5000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400