INFO: task kworker/u4:6:285 blocked for more than 143 seconds. Not tainted 5.10.0-rc4-next-20201118-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:6 state:D stack:24488 pid: 285 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4269 [inline] __schedule+0x890/0x2030 kernel/sched/core.c:5019 schedule+0xcf/0x270 kernel/sched/core.c:5098 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1847 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_stop+0x17a/0x720 kernel/kthread.c:596 io_put_sq_data fs/io_uring.c:7235 [inline] io_sq_thread_stop+0x452/0x570 fs/io_uring.c:7332 io_finish_async fs/io_uring.c:7339 [inline] io_ring_ctx_free fs/io_uring.c:8494 [inline] io_ring_exit_work+0x102/0x7a0 fs/io_uring.c:8588 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 INFO: task kworker/u4:8:428 blocked for more than 144 seconds. Not tainted 5.10.0-rc4-next-20201118-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:8 state:D stack:23424 pid: 428 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4269 [inline] __schedule+0x890/0x2030 kernel/sched/core.c:5019 schedule+0xcf/0x270 kernel/sched/core.c:5098 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1847 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_stop+0x17a/0x720 kernel/kthread.c:596 io_put_sq_data fs/io_uring.c:7235 [inline] io_sq_thread_stop+0x452/0x570 fs/io_uring.c:7332 io_finish_async fs/io_uring.c:7339 [inline] io_ring_ctx_free fs/io_uring.c:8494 [inline] io_ring_exit_work+0x102/0x7a0 fs/io_uring.c:8588 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 INFO: task kworker/u4:4:23220 blocked for more than 145 seconds. Not tainted 5.10.0-rc4-next-20201118-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:4 state:D stack:24856 pid:23220 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4269 [inline] __schedule+0x890/0x2030 kernel/sched/core.c:5019 schedule+0xcf/0x270 kernel/sched/core.c:5098 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1847 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_stop+0x17a/0x720 kernel/kthread.c:596 io_put_sq_data fs/io_uring.c:7235 [inline] io_sq_thread_stop+0x452/0x570 fs/io_uring.c:7332 io_finish_async fs/io_uring.c:7339 [inline] io_ring_ctx_free fs/io_uring.c:8494 [inline] io_ring_exit_work+0x102/0x7a0 fs/io_uring.c:8588 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Showing all locks held in the system: 2 locks held by kworker/u4:6/285: #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+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90001cefda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 2 locks held by kworker/u4:8/428: #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+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90001f7fda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 1 lock held by khungtaskd/1659: #0: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6252 1 lock held by systemd-udevd/4906: 1 lock held by in:imklog/8188: #0: ffff888012581c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932 4 locks held by syz-executor.0/8502: 3 locks held by syz-executor.1/8504: #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1318 [inline] #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x2030 kernel/sched/core.c:4936 #1: ffff8880b9f20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 #2: ffff8880b9f20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_change+0x142/0x220 kernel/sched/psi.c:807 1 lock held by syz-executor.2/8506: 3 locks held by syz-executor.4/8510: 3 locks held by syz-executor.5/8526: #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1318 [inline] #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x2030 kernel/sched/core.c:4936 #1: ffff8880b9e20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 #2: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: trace_sched_stat_runtime include/trace/events/sched.h:519 [inline] #2: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: update_curr+0x2e1/0x840 kernel/sched/fair.c:869 2 locks held by kworker/u4:4/23220: #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+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90017c0fda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 2 locks held by kworker/u4:5/19481: 3 locks held by syz-executor.3/26519: #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1318 [inline] #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x2030 kernel/sched/core.c:4936 #1: ffff8880b9f20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 #2: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: compound_head include/linux/page-flags.h:184 [inline] #2: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: lock_page_memcg+0x33/0x4f0 mm/memcontrol.c:2135 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1659 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201118-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+0x3af/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: 4899 Comm: systemd-journal Not tainted 5.10.0-rc4-next-20201118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:321 [inline] RIP: 0010:rcu_is_watching+0x63/0xc0 kernel/rcu/tree.c:1113 Code: 80 3c 02 00 75 5b 48 03 1c ed c0 a6 e4 8a 48 b8 00 00 00 00 00 fc ff df 48 8d bb 48 01 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1f 8b 83 48 01 00 RSP: 0018:ffffc9000166fae0 EFLAGS: 00000a06 RAX: dffffc0000000000 RBX: ffff8880b9e35dc0 RCX: ffffffff81569ad8 RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff8880b9e35f08 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ced3e8f R10: fffffbfff19da7d1 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888011b300d0 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f38db5378c0(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f38d8a8d000 CR3: 0000000011523000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:106 [inline] rcu_read_lock_sched_held+0x1c/0x70 kernel/rcu/update.c:121 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x6a6/0x8c0 kernel/locking/lockdep.c:5406 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103 devkmsg_read+0xbd/0x740 kernel/printk/printk.c:765 vfs_read+0x1b5/0x570 fs/read_write.c:494 ksys_read+0x12d/0x250 fs/read_write.c:634 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f38daac7210 Code: 73 01 c3 48 8b 0d 98 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 c1 20 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24 RSP: 002b:00007ffe9efff368 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007ffe9f001de0 RCX: 00007f38daac7210 RDX: 0000000000002000 RSI: 00007ffe9efffbe0 RDI: 0000000000000009 RBP: 0000000000000000 R08: 0000000000000008 R09: 00007ffe9f0de0f0 R10: 00000000000499f4 R11: 0000000000000246 R12: 00007ffe9efffbe0 R13: 00007ffe9f001d38 R14: 0000562d4708e958 R15: 0005b46d10c14591