===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.2.0-rc6 #6 Not tainted ----------------------------------------------------- syz-executor.2/11755 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 0000000052703db0 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 0000000052703db0 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read+0x3e7/0x1430 fs/userfaultfd.c:1045 and this task is already holding: 00000000c8e43739 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] 00000000c8e43739 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read+0x198/0x1430 fs/userfaultfd.c:1041 which would create a new lock dependency: (&ctx->fd_wqh){....} -> (&ctx->fault_pending_wqh){+.+.} but this new dependency connects a SOFTIRQ-irq-safe lock: (&(&ctx->ctx_lock)->rlock){..-.} ... which became SOFTIRQ-irq-safe at: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x6a/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x33/0x1d0 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline] percpu_ref_put+0x1c6/0x1d0 include/linux/percpu-refcount.h:301 percpu_ref_call_confirm_rcu lib/percpu-refcount.c:124 [inline] percpu_ref_switch_to_atomic_rcu+0x260/0x310 lib/percpu-refcount.c:159 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0x8d6/0xf90 kernel/rcu/tree.c:2291 __do_softirq+0x340/0x7b0 arch/x86/include/asm/paravirt.h:777 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x21a/0x230 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0xf8/0x260 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] lock_is_held_type+0x25c/0x2b0 kernel/locking/lockdep.c:4343 lock_is_held include/linux/lockdep.h:356 [inline] rcu_read_lock_sched_held+0x127/0x1c0 kernel/rcu/update.c:105 trace_kmalloc+0xcd/0x130 include/trace/events/kmem.h:46 kmem_cache_alloc_trace+0x222/0x2c0 mm/slab.c:3556 kmalloc include/linux/slab.h:547 [inline] kernfs_get_open_node fs/kernfs/file.c:571 [inline] kernfs_fop_open+0x92e/0xc20 fs/kernfs/file.c:717 do_dentry_open+0x7ba/0x1060 fs/open.c:778 vfs_open+0x73/0x80 fs/open.c:887 do_last fs/namei.c:3416 [inline] path_openat+0x136d/0x4400 fs/namei.c:3533 do_filp_open+0x1f7/0x430 fs/namei.c:3563 do_sys_open+0x343/0x620 fs/open.c:1070 __do_sys_open fs/open.c:1088 [inline] __se_sys_open fs/open.c:1083 [inline] __x64_sys_open+0x87/0x90 fs/open.c:1083 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe to a SOFTIRQ-irq-unsafe lock: (&ctx->fault_pending_wqh){+.+.} ... which became SOFTIRQ-irq-unsafe at: ... __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4dc/0x620 fs/userfaultfd.c:921 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x63f/0x2300 kernel/exit.c:877 do_group_exit+0x15c/0x2a0 kernel/exit.c:981 get_signal+0x6df/0x21f0 kernel/signal.c:2640 do_signal+0x7b/0x750 arch/x86/kernel/signal.c:815 exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x2f5/0x4f0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe 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 *** 1 lock held by syz-executor.2/11755: #0: 00000000c8e43739 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] #0: 00000000c8e43739 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read+0x198/0x1430 fs/userfaultfd.c:1041 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x6a/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x33/0x1d0 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline] percpu_ref_put+0x1c6/0x1d0 include/linux/percpu-refcount.h:301 percpu_ref_call_confirm_rcu lib/percpu-refcount.c:124 [inline] percpu_ref_switch_to_atomic_rcu+0x260/0x310 lib/percpu-refcount.c:159 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0x8d6/0xf90 kernel/rcu/tree.c:2291 __do_softirq+0x340/0x7b0 arch/x86/include/asm/paravirt.h:777 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x21a/0x230 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0xf8/0x260 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] lock_is_held_type+0x25c/0x2b0 kernel/locking/lockdep.c:4343 lock_is_held include/linux/lockdep.h:356 [inline] rcu_read_lock_sched_held+0x127/0x1c0 kernel/rcu/update.c:105 trace_kmalloc+0xcd/0x130 include/trace/events/kmem.h:46 kmem_cache_alloc_trace+0x222/0x2c0 mm/slab.c:3556 kmalloc include/linux/slab.h:547 [inline] kernfs_get_open_node fs/kernfs/file.c:571 [inline] kernfs_fop_open+0x92e/0xc20 fs/kernfs/file.c:717 do_dentry_open+0x7ba/0x1060 fs/open.c:778 vfs_open+0x73/0x80 fs/open.c:887 do_last fs/namei.c:3416 [inline] path_openat+0x136d/0x4400 fs/namei.c:3533 do_filp_open+0x1f7/0x430 fs/namei.c:3563 do_sys_open+0x343/0x620 fs/open.c:1070 __do_sys_open fs/open.c:1088 [inline] __se_sys_open fs/open.c:1083 [inline] __x64_sys_open+0x87/0x90 fs/open.c:1083 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x6a/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x33/0x1d0 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline] percpu_ref_put+0x1c6/0x1d0 include/linux/percpu-refcount.h:301 percpu_ref_call_confirm_rcu lib/percpu-refcount.c:124 [inline] percpu_ref_switch_to_atomic_rcu+0x260/0x310 lib/percpu-refcount.c:159 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0x8d6/0xf90 kernel/rcu/tree.c:2291 __do_softirq+0x340/0x7b0 arch/x86/include/asm/paravirt.h:777 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x21a/0x230 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0xf8/0x260 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] lock_is_held_type+0x25c/0x2b0 kernel/locking/lockdep.c:4343 lock_is_held include/linux/lockdep.h:356 [inline] rcu_read_lock_sched_held+0x127/0x1c0 kernel/rcu/update.c:105 trace_kmalloc+0xcd/0x130 include/trace/events/kmem.h:46 kmem_cache_alloc_trace+0x222/0x2c0 mm/slab.c:3556 kmalloc include/linux/slab.h:547 [inline] kernfs_get_open_node fs/kernfs/file.c:571 [inline] kernfs_fop_open+0x92e/0xc20 fs/kernfs/file.c:717 do_dentry_open+0x7ba/0x1060 fs/open.c:778 vfs_open+0x73/0x80 fs/open.c:887 do_last fs/namei.c:3416 [inline] path_openat+0x136d/0x4400 fs/namei.c:3533 do_filp_open+0x1f7/0x430 fs/namei.c:3563 do_sys_open+0x343/0x620 fs/open.c:1070 __do_sys_open fs/open.c:1088 [inline] __se_sys_open fs/open.c:1083 [inline] __x64_sys_open+0x87/0x90 fs/open.c:1083 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] ioctx_alloc.__key+0x0/0x10 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] aio_poll fs/aio.c:1752 [inline] __io_submit_one fs/aio.c:1826 [inline] io_submit_one+0x1167/0x1ac0 fs/aio.c:1863 __do_sys_io_submit fs/aio.c:1922 [inline] __se_sys_io_submit+0x18f/0x2d0 fs/aio.c:1892 __x64_sys_io_submit+0x7b/0x90 fs/aio.c:1892 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa1/0xc0 kernel/locking/spinlock.c:159 __wake_up_common_lock+0x105/0x240 kernel/sched/wait.c:121 __wake_up+0xe/0x10 kernel/sched/wait.c:146 userfaultfd_release+0x53a/0x620 fs/userfaultfd.c:929 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x63f/0x2300 kernel/exit.c:877 do_group_exit+0x15c/0x2a0 kernel/exit.c:981 get_signal+0x6df/0x21f0 kernel/signal.c:2640 do_signal+0x7b/0x750 arch/x86/kernel/signal.c:815 exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x2f5/0x4f0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] init_once_userfaultfd_ctx.__key.15+0x0/0x10 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read+0x3e7/0x1430 fs/userfaultfd.c:1045 userfaultfd_read+0x15d/0x2b0 fs/userfaultfd.c:1203 __vfs_read+0xf9/0x7c0 fs/read_write.c:425 vfs_read+0x195/0x3c0 fs/read_write.c:461 ksys_read+0x16b/0x2a0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:595 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (&ctx->fault_pending_wqh){+.+.} { HARDIRQ-ON-W at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4dc/0x620 fs/userfaultfd.c:921 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x63f/0x2300 kernel/exit.c:877 do_group_exit+0x15c/0x2a0 kernel/exit.c:981 get_signal+0x6df/0x21f0 kernel/signal.c:2640 do_signal+0x7b/0x750 arch/x86/kernel/signal.c:815 exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x2f5/0x4f0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4dc/0x620 fs/userfaultfd.c:921 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x63f/0x2300 kernel/exit.c:877 do_group_exit+0x15c/0x2a0 kernel/exit.c:981 get_signal+0x6df/0x21f0 kernel/signal.c:2640 do_signal+0x7b/0x750 arch/x86/kernel/signal.c:815 exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x2f5/0x4f0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4dc/0x620 fs/userfaultfd.c:921 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x63f/0x2300 kernel/exit.c:877 do_group_exit+0x15c/0x2a0 kernel/exit.c:981 get_signal+0x6df/0x21f0 kernel/signal.c:2640 do_signal+0x7b/0x750 arch/x86/kernel/signal.c:815 exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x2f5/0x4f0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] init_once_userfaultfd_ctx.__key+0x0/0x10 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read+0x3e7/0x1430 fs/userfaultfd.c:1045 userfaultfd_read+0x15d/0x2b0 fs/userfaultfd.c:1203 __vfs_read+0xf9/0x7c0 fs/read_write.c:425 vfs_read+0x195/0x3c0 fs/read_write.c:461 ksys_read+0x16b/0x2a0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:595 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 0 PID: 11755 Comm: syz-executor.2 Not tainted 5.2.0-rc6 #6 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+0x1d8/0x2f8 lib/dump_stack.c:113 print_bad_irq_dependency kernel/locking/lockdep.c:1920 [inline] check_irq_usage kernel/locking/lockdep.c:2114 [inline] check_prev_add kernel/locking/lockdep.c:2315 [inline] check_prevs_add kernel/locking/lockdep.c:2418 [inline] validate_chain+0x829b/0x84f0 kernel/locking/lockdep.c:2800 __lock_acquire+0xcf7/0x1a40 kernel/locking/lockdep.c:3793 lock_acquire+0x158/0x250 kernel/locking/lockdep.c:4303 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read+0x3e7/0x1430 fs/userfaultfd.c:1045 userfaultfd_read+0x15d/0x2b0 fs/userfaultfd.c:1203 __vfs_read+0xf9/0x7c0 fs/read_write.c:425 vfs_read+0x195/0x3c0 fs/read_write.c:461 ksys_read+0x16b/0x2a0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:595 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4592c9 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8d9f0ebc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004592c9 RDX: 0000000000000064 RSI: 0000000020000300 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8d9f0ec6d4 R13: 00000000004c53aa R14: 00000000004db138 R15: 00000000ffffffff