===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.0.0-rc3-next-20190123 #18 Not tainted ----------------------------------------------------- syz-executor4/18962 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 0000000004c9c39a (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline] 0000000004c9c39a (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read+0x690/0x2060 fs/userfaultfd.c:1040 and this task is already holding: 00000000c98e1f65 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:354 [inline] 00000000c98e1f65 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read+0x25e/0x2060 fs/userfaultfd.c:1036 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+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0xa7/0x6e0 fs/aio.c:610 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+0x50c/0x6b0 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2486 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0x94/0x120 kernel/locking/rwsem.c:26 anon_vma_lock_read include/linux/rmap.h:130 [inline] validate_mm+0xdb/0x620 mm/mmap.c:397 __vma_adjust+0xabb/0x1840 mm/mmap.c:998 vma_merge+0x439/0x1000 mm/mmap.c:1207 mmap_region+0x416/0x1ca0 mm/mmap.c:1746 do_mmap+0xa09/0x1220 mm/mmap.c:1559 do_mmap_pgoff include/linux/mm.h:2376 [inline] vm_mmap_pgoff+0x20b/0x2b0 mm/util.c:350 ksys_mmap_pgoff+0x102/0x650 mm/mmap.c:1609 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 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+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x613/0x8b0 fs/userfaultfd.c:916 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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_64+0x696/0x800 arch/x86/entry/common.c:293 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-executor4/18962: #0: 00000000c98e1f65 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:354 [inline] #0: 00000000c98e1f65 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read+0x25e/0x2060 fs/userfaultfd.c:1036 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0xa7/0x6e0 fs/aio.c:610 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+0x50c/0x6b0 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2486 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0x94/0x120 kernel/locking/rwsem.c:26 anon_vma_lock_read include/linux/rmap.h:130 [inline] validate_mm+0xdb/0x620 mm/mmap.c:397 __vma_adjust+0xabb/0x1840 mm/mmap.c:998 vma_merge+0x439/0x1000 mm/mmap.c:1207 mmap_region+0x416/0x1ca0 mm/mmap.c:1746 do_mmap+0xa09/0x1220 mm/mmap.c:1559 do_mmap_pgoff include/linux/mm.h:2376 [inline] vm_mmap_pgoff+0x20b/0x2b0 mm/util.c:350 ksys_mmap_pgoff+0x102/0x650 mm/mmap.c:1609 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0xa7/0x6e0 fs/aio.c:610 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+0x50c/0x6b0 lib/percpu-refcount.c:158 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2486 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0x94/0x120 kernel/locking/rwsem.c:26 anon_vma_lock_read include/linux/rmap.h:130 [inline] validate_mm+0xdb/0x620 mm/mmap.c:397 __vma_adjust+0xabb/0x1840 mm/mmap.c:998 vma_merge+0x439/0x1000 mm/mmap.c:1207 mmap_region+0x416/0x1ca0 mm/mmap.c:1746 do_mmap+0xa09/0x1220 mm/mmap.c:1559 do_mmap_pgoff include/linux/mm.h:2376 [inline] vm_mmap_pgoff+0x20b/0x2b0 mm/util.c:350 ksys_mmap_pgoff+0x102/0x650 mm/mmap.c:1609 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.52263+0x0/0x40 ... acquired at: __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+0x7b9/0x14e0 fs/aio.c:1772 __io_submit_one fs/aio.c:1875 [inline] io_submit_one+0xc39/0x1050 fs/aio.c:1908 __do_sys_io_submit fs/aio.c:1953 [inline] __se_sys_io_submit fs/aio.c:1923 [inline] __x64_sys_io_submit+0x1c4/0x5d0 fs/aio.c:1923 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x19b/0x390 kernel/sched/wait.c:120 __wake_up+0xe/0x10 kernel/sched/wait.c:145 userfaultfd_release+0x671/0x8b0 fs/userfaultfd.c:924 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.45190+0x0/0x40 ... acquired at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x690/0x2060 fs/userfaultfd.c:1040 userfaultfd_read+0x1e0/0x2c0 fs/userfaultfd.c:1198 __vfs_read+0x116/0xb20 fs/read_write.c:416 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0x105/0x260 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+0x1a3/0x800 arch/x86/entry/common.c:290 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+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x613/0x8b0 fs/userfaultfd.c:916 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x613/0x8b0 fs/userfaultfd.c:916 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x613/0x8b0 fs/userfaultfd.c:916 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.45187+0x0/0x40 ... acquired at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x690/0x2060 fs/userfaultfd.c:1040 userfaultfd_read+0x1e0/0x2c0 fs/userfaultfd.c:1198 __vfs_read+0x116/0xb20 fs/read_write.c:416 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0x105/0x260 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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 0 PID: 18962 Comm: syz-executor4 Not tainted 5.0.0-rc3-next-20190123 #18 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+0x1db/0x2d0 lib/dump_stack.c:113 print_bad_irq_dependency kernel/locking/lockdep.c:1574 [inline] check_usage.cold+0x5e2/0x917 kernel/locking/lockdep.c:1606 check_irq_usage kernel/locking/lockdep.c:1651 [inline] check_prev_add_irq kernel/locking/lockdep_states.h:8 [inline] check_prev_add kernel/locking/lockdep.c:1861 [inline] check_prevs_add kernel/locking/lockdep.c:1969 [inline] validate_chain kernel/locking/lockdep.c:2340 [inline] __lock_acquire+0x2142/0x4a10 kernel/locking/lockdep.c:3321 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3845 __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+0x690/0x2060 fs/userfaultfd.c:1040 userfaultfd_read+0x1e0/0x2c0 fs/userfaultfd.c:1198 __vfs_read+0x116/0xb20 fs/read_write.c:416 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0x105/0x260 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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458099 Code: 6d 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3cad909c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458099 RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3cad90a6d4 R13: 00000000004c3b5d R14: 00000000004d83b0 R15: 00000000ffffffff