===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.2.0-rc5+ #2 Not tainted ----------------------------------------------------- syz-executor.0/18622 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 000000005a049aa2 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 000000005a049aa2 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read fs/userfaultfd.c:1047 [inline] 000000005a049aa2 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1205 and this task is already holding: 000000003243b93d (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] 000000003243b93d (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1043 [inline] 000000003243b93d (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1205 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+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:285 [inline] percpu_ref_put include/linux/percpu-refcount.h:301 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:124 [inline] percpu_ref_switch_to_atomic_rcu+0x407/0x540 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+0xba5/0x1500 kernel/rcu/tree.c:2291 __do_softirq+0x25c/0x94c 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+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 check_memory_region_inline mm/kasan/generic.c:176 [inline] check_memory_region+0x13/0x190 mm/kasan/generic.c:191 atomic64_read include/asm-generic/atomic-instrumented.h:836 [inline] atomic_long_read include/asm-generic/atomic-long.h:28 [inline] __mutex_owner include/linux/mutex.h:75 [inline] mutex_spin_on_owner+0x88/0x330 kernel/locking/mutex.c:530 mutex_optimistic_spin kernel/locking/mutex.c:647 [inline] __mutex_lock_common kernel/locking/mutex.c:929 [inline] __mutex_lock+0x2b4/0x1310 kernel/locking/mutex.c:1073 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x40a/0xb00 net/core/rtnetlink.c:5211 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2482 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5232 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1333 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1922 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:665 __sys_sendto+0x262/0x380 net/socket.c:1958 __do_sys_sendto net/socket.c:1970 [inline] __se_sys_sendto net/socket.c:1966 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1966 do_syscall_64+0xfd/0x680 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: ... lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:923 __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:185 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x58e/0x680 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.0/18622: #0: 000000003243b93d (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] #0: 000000003243b93d (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1043 [inline] #0: 000000003243b93d (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1205 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:285 [inline] percpu_ref_put include/linux/percpu-refcount.h:301 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:124 [inline] percpu_ref_switch_to_atomic_rcu+0x407/0x540 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+0xba5/0x1500 kernel/rcu/tree.c:2291 __do_softirq+0x25c/0x94c 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+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806 check_memory_region_inline mm/kasan/generic.c:176 [inline] check_memory_region+0x13/0x190 mm/kasan/generic.c:191 atomic64_read include/asm-generic/atomic-instrumented.h:836 [inline] atomic_long_read include/asm-generic/atomic-long.h:28 [inline] __mutex_owner include/linux/mutex.h:75 [inline] mutex_spin_on_owner+0x88/0x330 kernel/locking/mutex.c:530 mutex_optimistic_spin kernel/locking/mutex.c:647 [inline] __mutex_lock_common kernel/locking/mutex.c:929 [inline] __mutex_lock+0x2b4/0x1310 kernel/locking/mutex.c:1073 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088 rtnl_lock net/core/rtnetlink.c:72 [inline] rtnetlink_rcv_msg+0x40a/0xb00 net/core/rtnetlink.c:5211 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2482 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5232 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1333 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1922 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:665 __sys_sendto+0x262/0x380 net/socket.c:1958 __do_sys_sendto net/socket.c:1970 [inline] __se_sys_sendto net/socket.c:1966 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1966 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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] aio_poll fs/aio.c:1750 [inline] __io_submit_one fs/aio.c:1826 [inline] io_submit_one+0xeb5/0x2ef0 fs/aio.c:1863 __do_sys_io_submit fs/aio.c:1922 [inline] __se_sys_io_submit fs/aio.c:1892 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1892 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.53435+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:1752 [inline] __io_submit_one fs/aio.c:1826 [inline] io_submit_one+0xefa/0x2ef0 fs/aio.c:1863 __do_sys_io_submit fs/aio.c:1922 [inline] __se_sys_io_submit fs/aio.c:1892 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1892 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 add_wait_queue+0x4c/0x170 kernel/sched/wait.c:23 aio_poll_queue_proc+0x9e/0x110 fs/aio.c:1715 poll_wait include/linux/poll.h:51 [inline] userfaultfd_poll+0x91/0x210 fs/userfaultfd.c:972 vfs_poll include/linux/poll.h:90 [inline] aio_poll fs/aio.c:1749 [inline] __io_submit_one fs/aio.c:1826 [inline] io_submit_one+0xe53/0x2ef0 fs/aio.c:1863 __do_sys_io_submit fs/aio.c:1922 [inline] __se_sys_io_submit fs/aio.c:1892 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1892 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.46111+0x0/0x40 ... acquired at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:1047 [inline] userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1205 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/0x680 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: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:923 __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:185 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:923 __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:185 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:923 __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:185 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x58e/0x680 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.46108+0x0/0x40 ... acquired at: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:1047 [inline] userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1205 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/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 0 PID: 18622 Comm: syz-executor.0 Not tainted 5.2.0-rc5+ #2 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:1920 [inline] check_irq_usage.cold+0x711/0xba0 kernel/locking/lockdep.c:2114 check_prev_add kernel/locking/lockdep.c:2315 [inline] check_prevs_add kernel/locking/lockdep.c:2418 [inline] validate_chain kernel/locking/lockdep.c:2800 [inline] __lock_acquire+0x2469/0x5490 kernel/locking/lockdep.c:3793 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303 __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:1047 [inline] userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1205 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/0x680 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:00007f36183f8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004592c9 RDX: 0000000000000001 RSI: 00000000200004c0 RDI: 0000000000000007 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f36183f96d4 R13: 00000000004c63fa R14: 00000000004db240 R15: 00000000ffffffff