===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.2.0-rc6-next-20190628 #25 Not tainted ----------------------------------------------------- syz-executor.4/15103 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 00000000a74d36e4 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 00000000a74d36e4 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] 00000000a74d36e4 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 and this task is already holding: 00000000bf7c0f9b (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] 00000000bf7c0f9b (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1041 [inline] 00000000bf7c0f9b (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1203 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: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x2d/0x490 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:293 [inline] percpu_ref_put include/linux/percpu-refcount.h:309 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:130 [inline] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 lib/percpu-refcount.c:165 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 lock_is_held_type+0x27f/0x320 kernel/locking/lockdep.c:4456 lock_is_held include/linux/lockdep.h:365 [inline] rcu_read_lock_sched_held+0x110/0x130 kernel/rcu/update.c:105 trace_kmem_cache_alloc include/trace/events/kmem.h:54 [inline] kmem_cache_alloc+0x361/0x710 mm/slab.c:3486 anon_vma_chain_alloc mm/rmap.c:129 [inline] anon_vma_clone+0xde/0x480 mm/rmap.c:269 anon_vma_fork+0x8f/0x4a0 mm/rmap.c:332 dup_mmap kernel/fork.c:547 [inline] dup_mm+0xa47/0x1430 kernel/fork.c:1347 copy_mm kernel/fork.c:1403 [inline] copy_process+0x28b7/0x6a90 kernel/fork.c:2042 _do_fork+0x146/0xfa0 kernel/fork.c:2379 __do_sys_clone kernel/fork.c:2521 [inline] __se_sys_clone kernel/fork.c:2501 [inline] __x64_sys_clone+0x186/0x250 kernel/fork.c:2501 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe to a SOFTIRQ-irq-unsafe lock: (&ctx->fault_pending_wqh){+.+.} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 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.4/15103: #0: 00000000bf7c0f9b (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] #0: 00000000bf7c0f9b (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1041 [inline] #0: 00000000bf7c0f9b (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1203 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x2d/0x490 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:293 [inline] percpu_ref_put include/linux/percpu-refcount.h:309 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:130 [inline] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 lib/percpu-refcount.c:165 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 lock_is_held_type+0x27f/0x320 kernel/locking/lockdep.c:4456 lock_is_held include/linux/lockdep.h:365 [inline] rcu_read_lock_sched_held+0x110/0x130 kernel/rcu/update.c:105 trace_kmem_cache_alloc include/trace/events/kmem.h:54 [inline] kmem_cache_alloc+0x361/0x710 mm/slab.c:3486 anon_vma_chain_alloc mm/rmap.c:129 [inline] anon_vma_clone+0xde/0x480 mm/rmap.c:269 anon_vma_fork+0x8f/0x4a0 mm/rmap.c:332 dup_mmap kernel/fork.c:547 [inline] dup_mm+0xa47/0x1430 kernel/fork.c:1347 copy_mm kernel/fork.c:1403 [inline] copy_process+0x28b7/0x6a90 kernel/fork.c:2042 _do_fork+0x146/0xfa0 kernel/fork.c:2379 __do_sys_clone kernel/fork.c:2521 [inline] __se_sys_clone kernel/fork.c:2501 [inline] __x64_sys_clone+0x186/0x250 kernel/fork.c:2501 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x2d/0x490 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:293 [inline] percpu_ref_put include/linux/percpu-refcount.h:309 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:130 [inline] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 lib/percpu-refcount.c:165 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 lock_is_held_type+0x27f/0x320 kernel/locking/lockdep.c:4456 lock_is_held include/linux/lockdep.h:365 [inline] rcu_read_lock_sched_held+0x110/0x130 kernel/rcu/update.c:105 trace_kmem_cache_alloc include/trace/events/kmem.h:54 [inline] kmem_cache_alloc+0x361/0x710 mm/slab.c:3486 anon_vma_chain_alloc mm/rmap.c:129 [inline] anon_vma_clone+0xde/0x480 mm/rmap.c:269 anon_vma_fork+0x8f/0x4a0 mm/rmap.c:332 dup_mmap kernel/fork.c:547 [inline] dup_mm+0xa47/0x1430 kernel/fork.c:1347 copy_mm kernel/fork.c:1403 [inline] copy_process+0x28b7/0x6a90 kernel/fork.c:2042 _do_fork+0x146/0xfa0 kernel/fork.c:2379 __do_sys_clone kernel/fork.c:2521 [inline] __se_sys_clone kernel/fork.c:2501 [inline] __x64_sys_clone+0x186/0x250 kernel/fork.c:2501 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.53845+0x0/0x40 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] aio_poll fs/aio.c:1750 [inline] __io_submit_one fs/aio.c:1824 [inline] io_submit_one+0xefa/0x2ef0 fs/aio.c:1861 __do_sys_io_submit fs/aio.c:1920 [inline] __se_sys_io_submit fs/aio.c:1890 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1890 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 __wake_up_common_lock+0xc8/0x150 kernel/sched/wait.c:122 __wake_up+0xe/0x10 kernel/sched/wait.c:142 userfaultfd_release+0x528/0x710 fs/userfaultfd.c:929 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.46560+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_readv+0x15b/0x330 fs/read_write.c:1034 __do_sys_readv fs/read_write.c:1125 [inline] __se_sys_readv fs/read_write.c:1122 [inline] __x64_sys_readv+0x75/0xb0 fs/read_write.c:1122 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 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: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.46557+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_readv+0x15b/0x330 fs/read_write.c:1034 __do_sys_readv fs/read_write.c:1125 [inline] __se_sys_readv fs/read_write.c:1122 [inline] __x64_sys_readv+0x75/0xb0 fs/read_write.c:1122 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 0 PID: 15103 Comm: syz-executor.4 Not tainted 5.2.0-rc6-next-20190628 #25 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_bad_irq_dependency kernel/locking/lockdep.c:2025 [inline] check_irq_usage.cold+0x5b4/0x72e kernel/locking/lockdep.c:2223 check_prev_add kernel/locking/lockdep.c:2409 [inline] check_prevs_add kernel/locking/lockdep.c:2507 [inline] validate_chain kernel/locking/lockdep.c:2897 [inline] __lock_acquire+0x25bd/0x4c20 kernel/locking/lockdep.c:3880 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_readv+0x15b/0x330 fs/read_write.c:1034 __do_sys_readv fs/read_write.c:1125 [inline] __se_sys_readv fs/read_write.c:1122 [inline] __x64_sys_readv+0x75/0xb0 fs/read_write.c:1122 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459519 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:00007f9640f25c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459519 RDX: 0000000000000001 RSI: 0000000020001640 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9640f266d4 R13: 00000000004c664d R14: 00000000004db780 R15: 00000000ffffffff