======================================================== WARNING: possible irq lock inversion dependency detected 5.1.0-rc4+ #67 Not tainted -------------------------------------------------------- udevd/9016 just changed the state of lock: 00000000a0afbde0 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:354 [inline] 00000000a0afbde0 (&(&ctx->ctx_lock)->rlock){..-.}, at: free_ioctx_users+0x2d/0x4a0 fs/aio.c:620 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 *** 5 locks held by udevd/9016: #0: 00000000a07876d1 (&mm->mmap_sem){++++}, at: do_user_addr_fault arch/x86/mm/fault.c:1416 [inline] #0: 00000000a07876d1 (&mm->mmap_sem){++++}, at: __do_page_fault+0x337/0xda0 arch/x86/mm/fault.c:1541 #1: 00000000787858a8 (rcu_read_lock){....}, at: filemap_map_pages+0x105/0x11e0 mm/filemap.c:2690 #2: 00000000f786bf66 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline] #2: 00000000f786bf66 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: pte_alloc_one_map mm/memory.c:3116 [inline] #2: 00000000f786bf66 (&(ptlock_ptr(page))->rlock#2){+.+.}, at: alloc_set_pte+0xf08/0x1900 mm/memory.c:3247 #3: 0000000001915d4f (rcu_callback){....}, at: __rcu_reclaim kernel/rcu/rcu.h:215 [inline] #3: 0000000001915d4f (rcu_callback){....}, at: rcu_do_batch kernel/rcu/tree.c:2475 [inline] #3: 0000000001915d4f (rcu_callback){....}, at: invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline] #3: 0000000001915d4f (rcu_callback){....}, at: rcu_core+0x9fb/0x13a0 kernel/rcu/tree.c:2769 #4: 0000000058668df5 (rcu_read_lock_sched){....}, at: percpu_ref_call_confirm_rcu lib/percpu-refcount.c:119 [inline] #4: 0000000058668df5 (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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_32_irqs_on arch/x86/entry/common.c:341 [inline] do_fast_syscall_32+0xa9d/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_32_irqs_on arch/x86/entry/common.c:341 [inline] do_fast_syscall_32+0xa9d/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 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+0x14f/0x2d0 fs/read_write.c:579 __do_sys_read fs/read_write.c:589 [inline] __se_sys_read fs/read_write.c:587 [inline] __ia32_sys_read+0x71/0xb0 fs/read_write.c:587 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 } ... key at: [] __key.45462+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+0x14f/0x2d0 fs/read_write.c:579 __do_sys_read fs/read_write.c:589 [inline] __se_sys_read fs/read_write.c:587 [inline] __ia32_sys_read+0x71/0xb0 fs/read_write.c:587 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 -> (&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 mremap_userfaultfd_complete+0x13b/0x1b0 fs/userfaultfd.c:775 __do_sys_mremap mm/mremap.c:725 [inline] __se_sys_mremap mm/mremap.c:594 [inline] __ia32_sys_mremap+0x61e/0xb7a mm/mremap.c:594 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 } ... key at: [] __key.45465+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:1752 [inline] __io_submit_one fs/aio.c:1826 [inline] io_submit_one+0xb27/0x2f40 fs/aio.c:1863 __do_compat_sys_io_submit fs/aio.c:1964 [inline] __se_compat_sys_io_submit fs/aio.c:1934 [inline] __ia32_compat_sys_io_submit+0x1be/0x570 fs/aio.c:1934 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 -> (&(&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:620 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+0x916/0x13a0 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 __read_once_size include/linux/compiler.h:193 [inline] check_kcov_mode kernel/kcov.c:70 [inline] __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:102 PageSwapBacked include/linux/page-flags.h:336 [inline] mm_counter_file include/linux/mm.h:1653 [inline] alloc_set_pte+0x32d/0x1900 mm/memory.c:3267 filemap_map_pages+0xf2b/0x11e0 mm/filemap.c:2743 do_fault_around mm/memory.c:3411 [inline] do_read_fault mm/memory.c:3445 [inline] do_fault mm/memory.c:3579 [inline] handle_pte_fault mm/memory.c:3810 [inline] __handle_mm_fault+0x31ed/0x3ec0 mm/memory.c:3934 handle_mm_fault+0x43f/0xb30 mm/memory.c:3971 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1541 do_page_fault+0x71/0x581 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 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:1750 [inline] __io_submit_one fs/aio.c:1826 [inline] io_submit_one+0xae2/0x2f40 fs/aio.c:1863 __do_compat_sys_io_submit fs/aio.c:1964 [inline] __se_compat_sys_io_submit fs/aio.c:1934 [inline] __ia32_compat_sys_io_submit+0x1be/0x570 fs/aio.c:1934 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 } ... key at: [] __key.52659+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:620 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+0x916/0x13a0 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 __read_once_size include/linux/compiler.h:193 [inline] check_kcov_mode kernel/kcov.c:70 [inline] __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:102 PageSwapBacked include/linux/page-flags.h:336 [inline] mm_counter_file include/linux/mm.h:1653 [inline] alloc_set_pte+0x32d/0x1900 mm/memory.c:3267 filemap_map_pages+0xf2b/0x11e0 mm/filemap.c:2743 do_fault_around mm/memory.c:3411 [inline] do_read_fault mm/memory.c:3445 [inline] do_fault mm/memory.c:3579 [inline] handle_pte_fault mm/memory.c:3810 [inline] __handle_mm_fault+0x31ed/0x3ec0 mm/memory.c:3934 handle_mm_fault+0x43f/0xb30 mm/memory.c:3971 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1541 do_page_fault+0x71/0x581 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 stack backtrace: CPU: 1 PID: 9016 Comm: udevd Not tainted 5.1.0-rc4+ #67 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:620 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+0x916/0x13a0 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:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:102 Code: 90 90 90 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 00 ee 01 00 65 8b 15 c8 60 91 7e 81 e2 00 01 1f 00 75 2b 8b 90 e0 12 00 00 <83> fa 02 75 20 48 8b 88 e8 12 00 00 8b 80 e4 12 00 00 48 8b 11 48 RSP: 0000:ffff88806bc3fb20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff888096492180 RBX: ffff88806bc3fd68 RCX: ffffffff819ba32b RDX: 0000000000000000 RSI: ffffffff819ba33d RDI: 0000000000000007 RBP: ffff88806bc3fb20 R08: ffff888096492180 R09: ffffed1015d25bc8 R10: ffffed1015d25bc7 R11: ffff8880ae92de3b R12: ffffea0000260288 R13: ffff888092a40778 R14: 000000000980a025 R15: ffffea0000260280 PageSwapBacked include/linux/page-flags.h:336 [inline] mm_counter_file include/linux/mm.h:1653 [inline] alloc_set_pte+0x32d/0x1900 mm/memory.c:3267 filemap_map_pages+0xf2b/0x11e0 mm/filemap.c:2743 do_fault_around mm/memory.c:3411 [inline] do_read_fault mm/memory.c:3445 [inline] do_fault mm/memory.c:3579 [inline] handle_pte_fault mm/memory.c:3810 [inline] __handle_mm_fault+0x31ed/0x3ec0 mm/memory.c:3934 handle_mm_fault+0x43f/0xb30 mm/memory.c:3971 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1541 do_page_fault+0x71/0x581 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 RIP: 0033:0x7fed9ce70590 Code: 00 74 0f f0 ff 0d ac 41 31 00 0f 85 d3 6b 00 00 eb 0c ff 0d 9e 41 31 00 0f 85 c5 6b 00 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 <8b> 0d 4e 1b 31 00 85 c9 7e 6c 48 8b 15 97 41 31 00 48 8b 05 78 17 RSP: 002b:00007fffb8710958 EFLAGS: 00010206 RAX: 00007fed9d184740 RBX: 00007fffb8710980 RCX: 00007fed9cbf62a0 RDX: 00007fed9ce70590 RSI: 00007fed9cbf2240 RDI: 00007fed9d1826c0 RBP: 00007fffb87109c0 R08: 0000000000001ecb R09: 0000000000001ecb R10: 00007fed9cbf2240 R11: 00007fed9d7c57a0 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fed9d7d0040 R15: 0000000000000005