INFO: task kworker/u4:1:22 blocked for more than 143 seconds. Not tainted 5.10.0-rc6-next-20201201-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:1 state:D stack:24352 pid: 22 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4325 [inline] __schedule+0x8cd/0x2150 kernel/sched/core.c:5076 schedule+0xcf/0x270 kernel/sched/core.c:5155 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1854 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x163/0x260 kernel/sched/completion.c:138 kthread_park+0x122/0x1b0 kernel/kthread.c:557 io_sq_thread_park fs/io_uring.c:7284 [inline] io_sq_thread_park fs/io_uring.c:7278 [inline] io_sq_thread_stop+0xfe/0x570 fs/io_uring.c:7302 io_finish_async fs/io_uring.c:7320 [inline] io_ring_ctx_free fs/io_uring.c:8487 [inline] io_ring_exit_work+0x102/0x7a0 fs/io_uring.c:8581 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Showing all locks held in the system: 3 locks held by kworker/u4:1/22: #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2243 #1: ffffc90000dcfda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2247 #2: ffff88802b7ec870 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7283 [inline] #2: ffff88802b7ec870 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7278 [inline] #2: ffff88802b7ec870 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_stop+0xd6/0x570 fs/io_uring.c:7302 2 locks held by kworker/u4:3/121: #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2243 #1: ffffc900012efda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2247 1 lock held by khungtaskd/1660: #0: ffffffff8b33a7a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254 1 lock held by in:imklog/8207: #0: ffff8880255a54f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:923 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1660 Comm: khungtaskd Not tainted 5.10.0-rc6-next-20201201-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd89/0xf30 kernel/hung_task.c:338 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4887 Comm: systemd-journal Not tainted 5.10.0-rc6-next-20201201-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:mark_lock+0x27/0x1730 kernel/locking/lockdep.c:4372 Code: 00 00 00 41 57 41 56 41 55 41 54 41 89 d4 48 ba 00 00 00 00 00 fc ff df 55 53 48 81 ec 10 01 00 00 48 8d 5c 24 30 48 89 3c 24 <48> c7 44 24 30 b3 8a b5 41 48 c1 eb 03 48 c7 44 24 38 50 e5 c7 8a RSP: 0018:ffffc900015ff990 EFLAGS: 00000086 RAX: 000000000000000c RBX: ffffc900015ff9c0 RCX: 1ffff11004a8d12d RDX: dffffc0000000000 RSI: ffff888025468970 RDI: ffff888025468000 RBP: ffff888025468000 R08: 0000000000000000 R09: ffffffff8ebd3767 R10: fffffbfff1d7a6ec R11: 0000000000000000 R12: 0000000000000008 R13: ffff888025468992 R14: ffffffff8f1c32d0 R15: 0000000000000000 FS: 00007f27cb04f8c0(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f27c84bc000 CR3: 00000000254b9000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_usage kernel/locking/lockdep.c:4332 [inline] __lock_acquire+0x8bb/0x5500 kernel/locking/lockdep.c:4786 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 __debug_check_no_obj_freed lib/debugobjects.c:975 [inline] debug_check_no_obj_freed+0xc7/0x420 lib/debugobjects.c:1018 slab_free_hook mm/slub.c:1540 [inline] slab_free_freelist_hook+0x12b/0x1d0 mm/slub.c:1586 slab_free mm/slub.c:3157 [inline] kmem_cache_free+0x8b/0x570 mm/slub.c:3173 __put_cred+0x1de/0x250 kernel/cred.c:148 put_cred include/linux/cred.h:287 [inline] put_cred include/linux/cred.h:280 [inline] revert_creds+0x1a8/0x1f0 kernel/cred.c:598 do_faccessat+0x2ca/0x820 fs/open.c:464 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f27ca30b9c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffd127aea38 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffd127b1950 RCX: 00007f27ca30b9c7 RDX: 00007f27cad7ca00 RSI: 0000000000000000 RDI: 0000564cf1a629a3 RBP: 00007ffd127aea70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffd127b1950 R15: 00007ffd127aef60