===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.0.0-rc3+ #40 Not tainted ----------------------------------------------------- syz-executor2/26459 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ------------[ cut here ]------------ 00000000c54e0356 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline] 00000000c54e0356 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read+0x690/0x2060 fs/userfaultfd.c:1040 downgrading a read lock WARNING: CPU: 1 PID: 3867 at kernel/locking/lockdep.c:3553 __lock_downgrade kernel/locking/lockdep.c:3553 [inline] WARNING: CPU: 1 PID: 3867 at kernel/locking/lockdep.c:3553 lock_downgrade+0x4d2/0x910 kernel/locking/lockdep.c:3816 and this task is already holding: Kernel panic - not syncing: panic_on_warn set ... 000000004cd69298 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:354 [inline] 000000004cd69298 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read+0x25e/0x2060 fs/userfaultfd.c:1036 CPU: 1 PID: 3867 Comm: udevd Not tainted 5.0.0-rc3+ #40 which would create a new lock dependency: Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 (&ctx->fd_wqh){....} -> (&ctx->fault_pending_wqh){+.+.} Call Trace: but this new dependency connects a SOFTIRQ-irq-safe lock: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 (&(&ctx->ctx_lock)->rlock){..-.} ... which became SOFTIRQ-irq-safe at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 panic+0x2cb/0x65c kernel/panic.c:214 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:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0xc4a/0x1680 kernel/rcu/tree.c:2754 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:654 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:646 smpboot_thread_fn+0x6ab/0xa10 kernel/smpboot.c:164 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 __warn.cold+0x20/0x48 kernel/panic.c:571 to a SOFTIRQ-irq-unsafe lock: (&ctx->fault_pending_wqh){+.+.} ... which became SOFTIRQ-irq-unsafe at: report_bug+0x263/0x2b0 lib/bug.c:186 ... lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 spin_lock include/linux/spinlock.h:329 [inline] handle_userfault+0x901/0x2510 fs/userfaultfd.c:461 do_anonymous_page mm/memory.c:2921 [inline] handle_pte_fault mm/memory.c:3785 [inline] __handle_mm_fault+0x4563/0x55a0 mm/memory.c:3911 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 handle_mm_fault+0x4ec/0xc80 mm/memory.c:3948 RIP: 0010:__lock_downgrade kernel/locking/lockdep.c:3553 [inline] RIP: 0010:lock_downgrade+0x4d2/0x910 kernel/locking/lockdep.c:3816 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5da/0xd60 arch/x86/mm/fault.c:1541 Code: 00 00 00 fc ff df 41 c6 04 06 f8 e9 1f ff ff ff 48 c7 c7 40 a9 4b 88 4c 89 8d 58 ff ff ff 48 89 85 60 ff ff ff e8 7e 10 e7 ff <0f> 0b 48 8b 85 60 ff ff ff 4c 8d 5d d8 4c 89 f1 48 ba 00 00 00 00 do_page_fault+0xe6/0x7d8 arch/x86/mm/fault.c:1572 RSP: 0018:ffff888097437bb8 EFLAGS: 00010082 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 RAX: 0000000000000000 RBX: 1ffff11012e86f7d RCX: 0000000000000000 __get_user_4+0x21/0x30 arch/x86/lib/getuser.S:76 RDX: 0000000000000000 RSI: ffffffff816854c6 RDI: 0000000000000006 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2991 RBP: ffff888097437c70 R08: ffff88809742a2c0 R09: fffffbfff1333331 __sys_setsockopt+0x1b0/0x3a0 net/socket.c:1902 R10: fffffbfff1333330 R11: ffffffff89999983 R12: ffff88809742a2c0 __do_sys_setsockopt net/socket.c:1913 [inline] __se_sys_setsockopt net/socket.c:1910 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 R13: ffffffff8b56caa0 R14: ffff888097437c08 R15: 0000000000000002 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 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 ---- ---- downgrade_write+0x76/0x270 kernel/locking/rwsem.c:147 lock(&ctx->fault_pending_wqh); local_irq_disable(); lock(&(&ctx->ctx_lock)->rlock); lock(&ctx->fd_wqh); __do_munmap+0xc5a/0xef0 mm/mmap.c:2823 lock(&(&ctx->ctx_lock)->rlock); __vm_munmap+0x139/0x1f0 mm/mmap.c:2848 *** DEADLOCK *** 1 lock held by syz-executor2/26459: #0: 000000004cd69298 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:354 [inline] #0: 000000004cd69298 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read+0x25e/0x2060 fs/userfaultfd.c:1036 __do_sys_munmap mm/mmap.c:2873 [inline] __se_sys_munmap mm/mmap.c:2870 [inline] __x64_sys_munmap+0x67/0x80 mm/mmap.c:2870 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 entry_SYSCALL_64_after_hwframe+0x49/0xbe spin_lock_irq include/linux/spinlock.h:354 [inline] free_ioctx_users+0xa7/0x6e0 fs/aio.c:610 RIP: 0033:0x7f75e8178d37 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 Code: f0 ff ff 73 01 c3 48 8b 0d fe c0 2a 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d1 c0 2a 00 31 d2 48 29 c2 64 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0xc4a/0x1680 kernel/rcu/tree.c:2754 RSP: 002b:00007ffd298543d8 EFLAGS: 00000206 ORIG_RAX: 000000000000000b __do_softirq+0x30b/0xb11 kernel/softirq.c:292 RAX: ffffffffffffffda RBX: 0000000000f88530 RCX: 00007f75e8178d37 run_ksoftirqd kernel/softirq.c:654 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:646 RDX: 0000000000000000 RSI: 0000000000001000 RDI: 00007f75e8a6e000 smpboot_thread_fn+0x6ab/0xa10 kernel/smpboot.c:164 RBP: 0000000000000000 R08: 00007f75e8a687a0 R09: 0000000000000000 kthread+0x357/0x430 kernel/kthread.c:246 R10: 1999999999999999 R11: 0000000000000206 R12: 0000000000000000 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 R13: 0000000000420298 R14: 00007ffd29854862 R15: 0000000000f76250 INITIAL USE at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __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:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0xc4a/0x1680 kernel/rcu/tree.c:2754 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:654 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:646 smpboot_thread_fn+0x6ab/0xa10 kernel/smpboot.c:164 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 } ... key at: [] __key.51948+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:3841 __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 handle_userfault+0xdfb/0x2510 fs/userfaultfd.c:487 do_anonymous_page mm/memory.c:2921 [inline] handle_pte_fault mm/memory.c:3785 [inline] __handle_mm_fault+0x4563/0x55a0 mm/memory.c:3911 handle_mm_fault+0x4ec/0xc80 mm/memory.c:3948 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5da/0xd60 arch/x86/mm/fault.c:1541 do_page_fault+0xe6/0x7d8 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 __get_user_4+0x21/0x30 arch/x86/lib/getuser.S:76 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2991 __sys_setsockopt+0x1b0/0x3a0 net/socket.c:1902 __do_sys_setsockopt net/socket.c:1913 [inline] __se_sys_setsockopt net/socket.c:1910 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.44853+0x0/0x40 ... acquired at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __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:3841 __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] handle_userfault+0x901/0x2510 fs/userfaultfd.c:461 do_anonymous_page mm/memory.c:2921 [inline] handle_pte_fault mm/memory.c:3785 [inline] __handle_mm_fault+0x4563/0x55a0 mm/memory.c:3911 handle_mm_fault+0x4ec/0xc80 mm/memory.c:3948 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5da/0xd60 arch/x86/mm/fault.c:1541 do_page_fault+0xe6/0x7d8 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 __get_user_4+0x21/0x30 arch/x86/lib/getuser.S:76 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2991 __sys_setsockopt+0x1b0/0x3a0 net/socket.c:1902 __do_sys_setsockopt net/socket.c:1913 [inline] __se_sys_setsockopt net/socket.c:1910 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __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] handle_userfault+0x901/0x2510 fs/userfaultfd.c:461 do_anonymous_page mm/memory.c:2921 [inline] handle_pte_fault mm/memory.c:3785 [inline] __handle_mm_fault+0x4563/0x55a0 mm/memory.c:3911 handle_mm_fault+0x4ec/0xc80 mm/memory.c:3948 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5da/0xd60 arch/x86/mm/fault.c:1541 do_page_fault+0xe6/0x7d8 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 __get_user_4+0x21/0x30 arch/x86/lib/getuser.S:76 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2991 __sys_setsockopt+0x1b0/0x3a0 net/socket.c:1902 __do_sys_setsockopt net/socket.c:1913 [inline] __se_sys_setsockopt net/socket.c:1910 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 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:3841 __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] handle_userfault+0x901/0x2510 fs/userfaultfd.c:461 do_anonymous_page mm/memory.c:2921 [inline] handle_pte_fault mm/memory.c:3785 [inline] __handle_mm_fault+0x4563/0x55a0 mm/memory.c:3911 handle_mm_fault+0x4ec/0xc80 mm/memory.c:3948 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5da/0xd60 arch/x86/mm/fault.c:1541 do_page_fault+0xe6/0x7d8 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 __get_user_4+0x21/0x30 arch/x86/lib/getuser.S:76 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2991 __sys_setsockopt+0x1b0/0x3a0 net/socket.c:1902 __do_sys_setsockopt net/socket.c:1913 [inline] __se_sys_setsockopt net/socket.c:1910 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.44850+0x0/0x40 ... acquired at: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __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: 26459 Comm: syz-executor2 Not tainted 5.0.0-rc3+ #40 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:1573 [inline] check_usage.cold+0x5e2/0x917 kernel/locking/lockdep.c:1605 check_irq_usage kernel/locking/lockdep.c:1661 [inline] check_prev_add_irq kernel/locking/lockdep_states.h:8 [inline] check_prev_add kernel/locking/lockdep.c:1871 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2350 [inline] __lock_acquire+0x2169/0x4a30 kernel/locking/lockdep.c:3338 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __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:00007f0320ccac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458099 RDX: 0000000000000064 RSI: 000000002060df9c RDI: 0000000000000004 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0320ccb6d4 R13: 00000000004c3b5d R14: 00000000004d83b0 R15: 00000000ffffffff Kernel Offset: disabled Rebooting in 86400 seconds..