======================================================== WARNING: possible irq lock inversion dependency detected 5.1.0-rc1 #28 Not tainted -------------------------------------------------------- udevd/8003 just changed the state of lock: 0000000090c6b20b (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:354 [inline] 0000000090c6b20b (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x4a0 fs/aio.c:621 but this lock took another, SOFTIRQ-unsafe lock in the past: (&ctx->fault_pending_wqh){+.+.} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Chain exists of: &(&ctx->ctx_lock)->rlock --> &ctx->fd_wqh --> &ctx->fault_pending_wqh Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->fault_pending_wqh); local_irq_disable(); lock(&(&ctx->ctx_lock)->rlock); lock(&ctx->fd_wqh); lock(&(&ctx->ctx_lock)->rlock); *** DEADLOCK *** 2 locks held by udevd/8003: #0: 000000009fae3c2f (rcu_callback){....}, at: __rcu_reclaim kernel/rcu/rcu.h:215 [inline] #0: 000000009fae3c2f (rcu_callback){....}, at: rcu_do_batch kernel/rcu/tree.c:2475 [inline] #0: 000000009fae3c2f (rcu_callback){....}, at: invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline] #0: 000000009fae3c2f (rcu_callback){....}, at: rcu_core+0xa0d/0x1390 kernel/rcu/tree.c:2769 #1: 000000009c572375 (rcu_read_lock_sched){....}, at: percpu_ref_call_confirm_rcu lib/percpu-refcount.c:119 [inline] #1: 000000009c572375 (rcu_read_lock_sched){....}, at: percpu_ref_switch_to_atomic_rcu+0x1b8/0x520 lib/percpu-refcount.c:158 the shortest dependencies between 2nd lock and 1st lock: -> (&ctx->fault_pending_wqh){+.+.} { HARDIRQ-ON-W at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 get_signal+0x1961/0x1d50 kernel/signal.c:2390 do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 get_signal+0x1961/0x1d50 kernel/signal.c:2390 do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline] userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198 __vfs_read+0x8d/0x110 fs/read_write.c:416 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0xea/0x1f0 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.45450+0x0/0x40 ... acquired at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline] userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198 __vfs_read+0x8d/0x110 fs/read_write.c:416 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0xea/0x1f0 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 __wake_up_common_lock+0xc7/0x190 kernel/sched/wait.c:120 __wake_up+0xe/0x10 kernel/sched/wait.c:145 userfaultfd_event_wait_completion+0x2c4/0xa50 fs/userfaultfd.c:618 userfaultfd_unmap_complete+0x264/0x400 fs/userfaultfd.c:856 __do_sys_mremap mm/mremap.c:726 [inline] __se_sys_mremap mm/mremap.c:594 [inline] __x64_sys_mremap+0x4b5/0xb80 mm/mremap.c:594 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.45453+0x0/0x40 ... acquired at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] aio_poll fs/aio.c:1762 [inline] __io_submit_one fs/aio.c:1868 [inline] io_submit_one+0xe35/0x1cf0 fs/aio.c:1901 __do_sys_io_submit fs/aio.c:1946 [inline] __se_sys_io_submit fs/aio.c:1916 [inline] __x64_sys_io_submit+0x1bd/0x580 fs/aio.c:1916 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 spin_lock_irq include/linux/spinlock.h:354 [inline] free_ioctx_users+0x2d/0x4a0 fs/aio.c:621 percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline] percpu_ref_put include/linux/percpu-refcount.h:301 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:123 [inline] percpu_ref_switch_to_atomic_rcu+0x3e7/0x520 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:227 [inline] rcu_do_batch kernel/rcu/tree.c:2475 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline] rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769 __do_softirq+0x266/0x95a kernel/softirq.c:293 invoke_softirq kernel/softirq.c:374 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:414 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] slab_alloc mm/slab.c:3385 [inline] kmem_cache_alloc+0x28b/0x6f0 mm/slab.c:3554 getname_flags fs/namei.c:138 [inline] getname_flags+0xd6/0x5b0 fs/namei.c:128 user_path_at_empty+0x2f/0x50 fs/namei.c:2606 user_path_at include/linux/namei.h:60 [inline] vfs_statx+0x129/0x200 fs/stat.c:187 vfs_stat include/linux/fs.h:3177 [inline] __do_sys_newstat+0xa4/0x130 fs/stat.c:341 __se_sys_newstat fs/stat.c:337 [inline] __x64_sys_newstat+0x54/0x80 fs/stat.c:337 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 spin_lock_irq include/linux/spinlock.h:354 [inline] aio_poll fs/aio.c:1761 [inline] __io_submit_one fs/aio.c:1868 [inline] io_submit_one+0xe0c/0x1cf0 fs/aio.c:1901 __do_sys_io_submit fs/aio.c:1946 [inline] __se_sys_io_submit fs/aio.c:1916 [inline] __x64_sys_io_submit+0x1bd/0x580 fs/aio.c:1916 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.52640+0x0/0x40 ... acquired at: mark_lock_irq kernel/locking/lockdep.c:3054 [inline] mark_lock+0x427/0x1380 kernel/locking/lockdep.c:3421 mark_irqflags kernel/locking/lockdep.c:3299 [inline] __lock_acquire+0x1654/0x3fb0 kernel/locking/lockdep.c:3653 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 spin_lock_irq include/linux/spinlock.h:354 [inline] free_ioctx_users+0x2d/0x4a0 fs/aio.c:621 percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline] percpu_ref_put include/linux/percpu-refcount.h:301 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:123 [inline] percpu_ref_switch_to_atomic_rcu+0x3e7/0x520 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:227 [inline] rcu_do_batch kernel/rcu/tree.c:2475 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline] rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769 __do_softirq+0x266/0x95a kernel/softirq.c:293 invoke_softirq kernel/softirq.c:374 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:414 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] slab_alloc mm/slab.c:3385 [inline] kmem_cache_alloc+0x28b/0x6f0 mm/slab.c:3554 getname_flags fs/namei.c:138 [inline] getname_flags+0xd6/0x5b0 fs/namei.c:128 user_path_at_empty+0x2f/0x50 fs/namei.c:2606 user_path_at include/linux/namei.h:60 [inline] vfs_statx+0x129/0x200 fs/stat.c:187 vfs_stat include/linux/fs.h:3177 [inline] __do_sys_newstat+0xa4/0x130 fs/stat.c:341 __se_sys_newstat fs/stat.c:337 [inline] __x64_sys_newstat+0x54/0x80 fs/stat.c:337 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 1 PID: 8003 Comm: udevd Not tainted 5.1.0-rc1 #28 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+0x172/0x1f0 lib/dump_stack.c:113 print_irq_inversion_bug.part.0+0x2c0/0x2cd kernel/locking/lockdep.c:2920 print_irq_inversion_bug kernel/locking/lockdep.c:2923 [inline] check_usage_forwards.cold+0x20/0x29 kernel/locking/lockdep.c:2945 mark_lock_irq kernel/locking/lockdep.c:3054 [inline] mark_lock+0x427/0x1380 kernel/locking/lockdep.c:3421 mark_irqflags kernel/locking/lockdep.c:3299 [inline] __lock_acquire+0x1654/0x3fb0 kernel/locking/lockdep.c:3653 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 spin_lock_irq include/linux/spinlock.h:354 [inline] free_ioctx_users+0x2d/0x4a0 fs/aio.c:621 percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline] percpu_ref_put include/linux/percpu-refcount.h:301 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:123 [inline] percpu_ref_switch_to_atomic_rcu+0x3e7/0x520 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:227 [inline] rcu_do_batch kernel/rcu/tree.c:2475 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline] rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769 __do_softirq+0x266/0x95a kernel/softirq.c:293 invoke_softirq kernel/softirq.c:374 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:414 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] RIP: 0010:slab_alloc mm/slab.c:3385 [inline] RIP: 0010:kmem_cache_alloc+0x28b/0x6f0 mm/slab.c:3554 Code: 7e 0f 85 cd fe ff ff e8 f4 61 58 ff e9 c3 fe ff ff e8 39 d5 cd ff 48 83 3d d1 91 ea 06 00 0f 84 15 03 00 00 48 8b 7d d0 57 9d <0f> 1f 44 00 00 e9 60 fe ff ff 31 d2 be a1 01 00 00 48 c7 c7 a2 0b RSP: 0018:ffff88805791fc08 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000cc0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000282 RBP: ffff88805791fc70 R08: ffff8880a90dc340 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88812c2d8dc0 R13: ffff88812c2d8dc0 R14: 0000000000000cc0 R15: ffff888055400000 getname_flags fs/namei.c:138 [inline] getname_flags+0xd6/0x5b0 fs/namei.c:128 user_path_at_empty+0x2f/0x50 fs/namei.c:2606 user_path_at include/linux/namei.h:60 [inline] vfs_statx+0x129/0x200 fs/stat.c:187 vfs_stat include/linux/fs.h:3177 [inline] __do_sys_newstat+0xa4/0x130 fs/stat.c:341 __se_sys_newstat fs/stat.c:337 [inline] __x64_sys_newstat+0x54/0x80 fs/stat.c:337 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7ff4415ddc65 Code: 00 00 00 e8 5d 01 00 00 48 83 c4 18 c3 90 90 90 90 90 90 90 90 83 ff 01 48 89 f0 77 18 48 89 c7 48 89 d6 b8 04 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 17 f3 c3 90 48 8b 05 a1 51 2b 00 64 c7 00 16 RSP: 002b:00007ffe3345aa38 EFLAGS: 00000246 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000b35250 RCX: 00007ff4415ddc65 RDX: 00007ffe3345aa50 RSI: 00007ffe3345aa50 RDI: 00007ffe3345aee0 RBP: 0000000000b451e0 R08: 000000000041f4f1 R09: 00007ff4416347d0 R10: 7269762f73656369 R11: 0000000000000246 R12: 0000000000000004 R13: 0000000000b451e7 R14: 0000000000b35250 R15: 000000000000000b