======================================================== WARNING: possible irq lock inversion dependency detected 5.9.0-syzkaller #0 Not tainted -------------------------------------------------------- kworker/u4:3/45 just changed the state of lock: ffff88809a2ec908 (&group->lock){..-.}-{2:2}, at: snd_pcm_period_elapsed+0x2c/0x210 sound/core/pcm_lib.c:1799 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 *** 4 locks held by kworker/u4:3/45: #0: ffff888098f85138 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x6f4/0xfc0 kernel/workqueue.c:2242 #1: ffffc90000f27d80 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x733/0xfc0 kernel/workqueue.c:2244 #2: ffffffff8a8f72c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:240 #3: ffffc90000007db0 ((&dpcm->timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline] #3: ffffc90000007db0 ((&dpcm->timer)){+.-.}-{0:0}, at: call_timer_fn+0x57/0x160 kernel/time/timer.c:1405 the shortest dependencies between 2nd lock and 1st 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 USE at: lock_acquire+0x160/0x6e0 kernel/locking/lockdep.c:5442 __raw_write_lock_irqsave include/linux/rwlock_api_smp.h:186 [inline] _raw_write_lock_irqsave+0xaa/0xd0 kernel/locking/spinlock.c:303 snd_ctl_open+0x314/0x450 sound/core/control.c:74 chrdev_open+0x4a0/0x570 fs/char_dev.c:414 do_dentry_open+0x7c8/0x1010 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x27af/0x37c0 fs/namei.c:3368 do_filp_open+0x191/0x3a0 fs/namei.c:3395 do_sys_openat2+0x460/0x830 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x1af/0x1e0 fs/open.c:1188 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 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: [] 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:358 [inline] loopback_trigger+0xddb/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_plug_write_transfer+0x28b/0x490 sound/core/oss/pcm_plugin.c:624 snd_pcm_oss_write2+0x156/0x370 sound/core/oss/pcm_oss.c:1353 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 -> (&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+0x3a/0x50 arch/x86/include/asm/paravirt.h:653 lock_is_held_type+0xe2/0x120 kernel/locking/lockdep.c:5483 lock_is_held include/linux/lockdep.h:271 [inline] rcu_read_lock_sched_held+0x2f/0xa0 kernel/rcu/update.c:136 trace_lock_release+0x61/0x140 include/trace/events/lock.h:58 lock_release+0x27/0x720 kernel/locking/lockdep.c:5453 rcu_read_unlock include/linux/rcupdate.h:688 [inline] batadv_nc_process_nc_paths+0x2f1/0x380 net/batman-adv/network-coding.c:698 batadv_nc_worker+0x3ee/0x5c0 net/batman-adv/network-coding.c:727 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 kthread+0x371/0x390 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 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_make_ready+0x115/0x2b0 sound/core/oss/pcm_oss.c:1143 snd_pcm_oss_sync+0x26d/0x940 sound/core/oss/pcm_oss.c:1642 snd_pcm_oss_release+0x119/0x270 sound/core/oss/pcm_oss.c:2546 __fput+0x34f/0x7b0 fs/file_table.c:281 task_work_run+0x137/0x1c0 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:165 [inline] exit_to_user_mode_prepare+0x11d/0x1e0 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x82/0x1c0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 } ... key at: [] snd_pcm_group_init.__key+0x0/0x40 ... acquired at: mark_usage kernel/locking/lockdep.c:4305 [inline] __lock_acquire+0x9ee/0x6a40 kernel/locking/lockdep.c:4791 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+0x3a/0x50 arch/x86/include/asm/paravirt.h:653 lock_is_held_type+0xe2/0x120 kernel/locking/lockdep.c:5483 lock_is_held include/linux/lockdep.h:271 [inline] rcu_read_lock_sched_held+0x2f/0xa0 kernel/rcu/update.c:136 trace_lock_release+0x61/0x140 include/trace/events/lock.h:58 lock_release+0x27/0x720 kernel/locking/lockdep.c:5453 rcu_read_unlock include/linux/rcupdate.h:688 [inline] batadv_nc_process_nc_paths+0x2f1/0x380 net/batman-adv/network-coding.c:698 batadv_nc_worker+0x3ee/0x5c0 net/batman-adv/network-coding.c:727 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 kthread+0x371/0x390 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 stack backtrace: CPU: 0 PID: 45 Comm: kworker/u4:3 Not tainted 5.9.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 print_irq_inversion_bug+0xa5d/0xde0 kernel/locking/lockdep.c:3817 check_usage_forwards kernel/locking/lockdep.c:2470 [inline] mark_lock_irq kernel/locking/lockdep.c:3980 [inline] mark_lock+0x111b/0x1e20 kernel/locking/lockdep.c:4408 mark_usage kernel/locking/lockdep.c:4305 [inline] __lock_acquire+0x9ee/0x6a40 kernel/locking/lockdep.c:4791 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 RIP: 0010:arch_local_irq_restore+0x3a/0x50 arch/x86/include/asm/paravirt.h:653 Code: b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 0c 48 c7 c7 68 a1 76 8a e8 35 84 5d 00 48 83 3d 45 28 1a 09 00 74 0c 48 89 df 57 9d <0f> 1f 44 00 00 5b c3 0f 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc90000f27b28 EFLAGS: 00000282 RAX: 1ffffffff14ed42d RBX: 0000000000000282 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000282 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff17054c6 R10: fffffbfff17054c6 R11: 0000000000000000 R12: ffffffff8a8f7220 R13: ffff8880a9192040 R14: 00000000ffffffff R15: 0000000000000282 lock_is_held_type+0xe2/0x120 kernel/locking/lockdep.c:5483 lock_is_held include/linux/lockdep.h:271 [inline] rcu_read_lock_sched_held+0x2f/0xa0 kernel/rcu/update.c:136 trace_lock_release+0x61/0x140 include/trace/events/lock.h:58 lock_release+0x27/0x720 kernel/locking/lockdep.c:5453 rcu_read_unlock include/linux/rcupdate.h:688 [inline] batadv_nc_process_nc_paths+0x2f1/0x380 net/batman-adv/network-coding.c:698 batadv_nc_worker+0x3ee/0x5c0 net/batman-adv/network-coding.c:727 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 kthread+0x371/0x390 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296