======================================================== WARNING: possible irq lock inversion dependency detected 5.9.0-rc5-next-20200918-syzkaller #0 Not tainted -------------------------------------------------------- swapper/1/0 just changed the state of lock: ffff8882153f6108 (&group->lock){..-.}-{2:2}, at: _snd_pcm_stream_lock_irqsave+0x9f/0xd0 sound/core/pcm_native.c:170 but this lock took another, SOFTIRQ-READ-unsafe lock in the past: (&card->ctl_files_rwlock){.+.+}-{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(&card->ctl_files_rwlock); local_irq_disable(); lock(&group->lock); lock(&card->ctl_files_rwlock); lock(&group->lock); *** DEADLOCK *** 1 lock held by swapper/1/0: #0: ffffc90000da8d80 ((&dpcm->timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:35 [inline] #0: ffffc90000da8d80 ((&dpcm->timer)){+.-.}-{0:0}, at: call_timer_fn+0xd5/0x6b0 kernel/time/timer.c:1403 the shortest dependencies between 2nd lock and 1st 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+0xc22/0x1180 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:2928 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+0x1e0/0x309 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+0x652/0x6d6 init/main.c:1512 kernel_init+0xd/0x1b8 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+0xc22/0x1180 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:2928 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+0x1e0/0x309 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+0x652/0x6d6 init/main.c:1512 kernel_init+0xd/0x1b8 init/main.c:1402 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 (null) at: ================================================================================ UBSAN: array-index-out-of-bounds in kernel/locking/lockdep.c:2240:40 index 9 is out of range for type 'lock_trace *[9]' CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.9.0-rc5-next-20200918-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+0x198/0x1fb lib/dump_stack.c:118 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148 __ubsan_handle_out_of_bounds.cold+0x62/0x6c lib/ubsan.c:356 print_lock_class_header kernel/locking/lockdep.c:2240 [inline] print_shortest_lock_dependencies.cold+0x11c/0x2e2 kernel/locking/lockdep.c:2263 print_irq_inversion_bug.part.0+0x2c6/0x2ee kernel/locking/lockdep.c:3769 print_irq_inversion_bug kernel/locking/lockdep.c:4377 [inline] check_usage_forwards kernel/locking/lockdep.c:3803 [inline] mark_lock_irq kernel/locking/lockdep.c:3935 [inline] mark_lock.cold+0x57/0x74 kernel/locking/lockdep.c:4375 mark_usage kernel/locking/lockdep.c:4260 [inline] __lock_acquire+0x118a/0x56d0 kernel/locking/lockdep.c:4750 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+0xb3/0x1d0 kernel/time/timer.c:1768 __do_softirq+0x203/0xab6 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:786 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: 89 ef e8 a5 99 76 f9 e9 86 fe ff ff 48 89 df e8 98 99 76 f9 e9 7b ff ff ff cc cc cc e9 07 00 00 00 0f 00 2d c4 14 49 00 fb f4 90 e9 07 00 00 00 0f 00 2d b4 14 49 00 f4 c3 cc cc 55 53 e8 09 RSP: 0018:ffffc90000d3fd80 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffffffff171e639 RDX: ffff8880a961a340 RSI: ffffffff883fd4d3 RDI: 0000000000000000 RBP: ffff88821a913064 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 R13: ffff88821a913000 R14: ffff88821a913064 R15: ffff8882185fc004 arch_safe_halt arch/x86/include/asm/paravirt.h:150 [inline] acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline] acpi_idle_do_entry+0x1e8/0x330 drivers/acpi/processor_idle.c:516 acpi_idle_enter+0x35a/0x550 drivers/acpi/processor_idle.c:647 cpuidle_enter_state+0x1ab/0xd20 drivers/cpuidle/cpuidle.c:247 cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:360 call_cpuidle kernel/sched/idle.c:132 [inline] cpuidle_idle_call kernel/sched/idle.c:213 [inline] do_idle+0x48e/0x730 kernel/sched/idle.c:273 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:369 secondary_startup_64_no_verify+0xa6/0xab ================================================================================