======================================================== WARNING: possible irq lock inversion dependency detected 4.19.0+ #306 Not tainted -------------------------------------------------------- syz-executor911/5551 just changed the state of lock: 00000000758a85c4 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline] 00000000758a85c4 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_release+0x63e/0x8d0 fs/userfaultfd.c:909 but this lock was taken by another, SOFTIRQ-safe lock in the past: (&(&ctx->ctx_lock)->rlock){..-.} 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 *** no locks held by syz-executor911/5551. the shortest dependencies between 2nd lock and 1st lock: -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x61/0x80 kernel/locking/spinlock.c:160 spin_lock_irq include/linux/spinlock.h:354 [inline] free_ioctx_users+0xbc/0x710 fs/aio.c:603 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+0x563/0x730 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2437 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline] rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697 __do_softirq+0x308/0xb7e kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:801 native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57 arch_safe_halt arch/x86/include/asm/paravirt.h:151 [inline] default_idle+0xbf/0x490 arch/x86/kernel/process.c:498 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x49b/0x5c0 kernel/sched/idle.c:262 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:353 rest_init+0x243/0x372 init/main.c:442 arch_call_rest_init+0xe/0x1b start_kernel+0xa1f/0xa5a init/main.c:744 x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 INITIAL USE at: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x61/0x80 kernel/locking/spinlock.c:160 spin_lock_irq include/linux/spinlock.h:354 [inline] aio_poll+0x738/0x1420 fs/aio.c:1746 io_submit_one+0xa49/0xf80 fs/aio.c:1850 __do_sys_io_submit fs/aio.c:1916 [inline] __se_sys_io_submit fs/aio.c:1887 [inline] __x64_sys_io_submit+0x1b7/0x580 fs/aio.c:1887 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.50665+0x0/0x40 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] aio_poll+0x760/0x1420 fs/aio.c:1747 io_submit_one+0xa49/0xf80 fs/aio.c:1850 __do_sys_io_submit fs/aio.c:1916 [inline] __se_sys_io_submit fs/aio.c:1887 [inline] __x64_sys_io_submit+0x1b7/0x580 fs/aio.c:1887 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152 add_wait_queue+0x92/0x2b0 kernel/sched/wait.c:22 aio_poll_queue_proc+0xa1/0x100 fs/aio.c:1705 poll_wait include/linux/poll.h:47 [inline] userfaultfd_poll+0xff/0x3a0 fs/userfaultfd.c:958 vfs_poll include/linux/poll.h:86 [inline] aio_poll+0x6ad/0x1420 fs/aio.c:1740 io_submit_one+0xa49/0xf80 fs/aio.c:1850 __do_sys_io_submit fs/aio.c:1916 [inline] __se_sys_io_submit fs/aio.c:1887 [inline] __x64_sys_io_submit+0x1b7/0x580 fs/aio.c:1887 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.44286+0x0/0x40 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_ctx_read+0x4f3/0x2180 fs/userfaultfd.c:1033 userfaultfd_read+0x1e2/0x2c0 fs/userfaultfd.c:1191 __vfs_read+0x117/0x9b0 fs/read_write.c:416 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_read+0x101/0x260 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+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fault_pending_wqh){+.+.} { HARDIRQ-ON-W at: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_release+0x63e/0x8d0 fs/userfaultfd.c:909 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1ad6/0x26d0 kernel/exit.c:867 do_group_exit+0x177/0x440 kernel/exit.c:970 get_signal+0x8b0/0x1980 kernel/signal.c:2517 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 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+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_release+0x63e/0x8d0 fs/userfaultfd.c:909 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1ad6/0x26d0 kernel/exit.c:867 do_group_exit+0x177/0x440 kernel/exit.c:970 get_signal+0x8b0/0x1980 kernel/signal.c:2517 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 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+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_ctx_read+0x4f3/0x2180 fs/userfaultfd.c:1033 userfaultfd_read+0x1e2/0x2c0 fs/userfaultfd.c:1191 __vfs_read+0x117/0x9b0 fs/read_write.c:416 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_read+0x101/0x260 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+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.44283+0x0/0x40 ... acquired at: mark_lock_irq kernel/locking/lockdep.c:2687 [inline] mark_lock+0x9b5/0x1cd0 kernel/locking/lockdep.c:3059 mark_irqflags kernel/locking/lockdep.c:2955 [inline] __lock_acquire+0xd15/0x4c20 kernel/locking/lockdep.c:3298 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_release+0x63e/0x8d0 fs/userfaultfd.c:909 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1ad6/0x26d0 kernel/exit.c:867 do_group_exit+0x177/0x440 kernel/exit.c:970 get_signal+0x8b0/0x1980 kernel/signal.c:2517 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 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+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 0 PID: 5551 Comm: syz-executor911 Not tainted 4.19.0+ #306 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+0x244/0x39d lib/dump_stack.c:113 print_irq_inversion_bug.part.37+0x2c7/0x2d6 kernel/locking/lockdep.c:2553 print_irq_inversion_bug kernel/locking/lockdep.c:2556 [inline] check_usage_backwards.cold.56+0x1d/0x26 kernel/locking/lockdep.c:2602 mark_lock_irq kernel/locking/lockdep.c:2687 [inline] mark_lock+0x9b5/0x1cd0 kernel/locking/lockdep.c:3059 mark_irqflags kernel/locking/lockdep.c:2955 [inline] __lock_acquire+0xd15/0x4c20 kernel/locking/lockdep.c:3298 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] userfaultfd_release+0x63e/0x8d0 fs/userfaultfd.c:909 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1ad6/0x26d0 kernel/exit.c:867 do_group_exit+0x177/0x440 kernel/exit.c:970 get_signal+0x8b0/0x1980 kernel/signal.c:2517 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 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+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440e99 Code: Bad RIP value. RSP: 002b:00007ffd69bf8a18 EFLAGS: 00000217 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 0000000000000000 RCX: 0000000000440e99 RDX: 0000000000000064 RSI: 0000000020009f9c RDI: 0000000000000004 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000217 R12: 0000000000401de0 R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000