INFO: task kworker/u4:5:8216 blocked for more than 143 seconds. Not tainted 5.9.0-rc4-next-20200908-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:5 state:D stack:23904 pid: 8216 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:3777 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4526 schedule+0xcf/0x270 kernel/sched/core.c:4604 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855 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_stop+0xbb/0x5d0 fs/io_uring.c:7108 io_finish_async fs/io_uring.c:7125 [inline] io_ring_ctx_free fs/io_uring.c:8192 [inline] io_ring_exit_work+0xfe/0x5f0 fs/io_uring.c:8275 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Showing all locks held in the system: 1 lock held by khungtaskd/1158: #0: ffffffff89c68540 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6221 2 locks held by kworker/1:2/2586: #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880aa073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90008527da8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 1 lock held by in:imklog/6548: #0: ffff88809758ee30 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 2 locks held by agetty/6785: #0: ffff8880a78d8098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffffc900032762e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by agetty/6786: #0: ffff8880a69ac098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffffc900033fe2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/6886: #0: ffff88808abc52c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 #1: ffffffff8a3674a8 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1893 2 locks held by kworker/u4:5/8216: #0: ffff8880aa071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880aa071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880aa071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880aa071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880aa071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900161d7da8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 2 locks held by syz-executor.0/10098: #0: ffff88809c860240 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 #1: ffffffff8a3674a8 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1893 1 lock held by systemd-udevd/12108: #0: ffff88808abc5940 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 1 lock held by systemd-udevd/12159: #0: ffff8880a9c050c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 1 lock held by systemd-udevd/12187: #0: ffff88809c860240 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 1 lock held by systemd-udevd/13232: #0: ffff88808abc8980 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 1 lock held by systemd-udevd/18325: #0: ffff88808abc52c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 1 lock held by systemd-udevd/18348: #0: ffff88808abc8300 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1508 3 locks held by kworker/u4:7/31226: 2 locks held by syz-executor.5/16176: #0: ffff88808abc8980 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1799 #1: ffffffff8a3674a8 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1912 2 locks held by syz-executor.1/16204: #0: ffff8880a9c050c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1799 #1: ffffffff8a3674a8 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1912 2 locks held by syz-executor.1/16206: #0: ffff88805298a0e0 (&type->s_umount_key#64/1){+.+.}-{3:3}, at: alloc_super+0x201/0xa90 fs/super.c:229 #1: ffffffff89c6d228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #1: ffffffff89c6d228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x274/0x5f0 kernel/rcu/tree_exp.h:836 2 locks held by syz-executor.2/16211: #0: ffff88808abc8300 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1799 #1: ffffffff8a3674a8 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1912 1 lock held by syz-executor.2/16223: #0: ffff888061e9e0e0 (&type->s_umount_key#64/1){+.+.}-{3:3}, at: alloc_super+0x201/0xa90 fs/super.c:229 2 locks held by syz-executor.4/16219: #0: ffff88808abc5940 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1799 #1: ffffffff8a3674a8 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1912 2 locks held by syz-executor.4/16220: #0: ffff888058afe0e0 (&type->s_umount_key#64/1){+.+.}-{3:3}, at: alloc_super+0x201/0xa90 fs/super.c:229 #1: ffffffff89c6d228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #1: ffffffff89c6d228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x274/0x5f0 kernel/rcu/tree_exp.h:836 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1158 Comm: khungtaskd Not tainted 5.9.0-rc4-next-20200908-syzkaller #0 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+0x198/0x1fb lib/dump_stack.c:118 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:339 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 16248 Comm: syz-executor.0 Not tainted 5.9.0-rc4-next-20200908-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:generic_file_write_iter+0x4d/0x5c0 mm/filemap.c:3576 Code: b3 8a b5 41 4c 8d 6c 24 20 48 c7 44 24 28 c0 d5 6c 89 49 c1 ed 03 48 c7 44 24 30 50 c5 93 81 4b 8d 44 25 00 c7 00 f1 f1 f1 f1 40 04 00 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 44 24 78 31 RSP: 0018:ffffc90015d57c58 EFLAGS: 00000a02 RAX: fffff52002baaf8f RBX: ffffc90015d57db0 RCX: ffffc9000b0d5000 RDX: 1ffffffff10a8f91 RSI: ffffc90015d57d60 RDI: ffffc90015d57db0 RBP: ffffc90015d57d60 R08: 0000000000000000 R09: ffffffff8c6b4a77 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 1ffff92002baaf8f R14: ffffc90015d57ed0 R15: 0000000000000000 FS: 00007fd8f04f4700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3926bfe000 CR3: 00000000918e1000 CR4: 00000000001526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: call_write_iter include/linux/fs.h:1892 [inline] new_sync_write+0x422/0x650 fs/read_write.c:517 vfs_write+0x57d/0x700 fs/read_write.c:595 ksys_pwrite64 fs/read_write.c:702 [inline] __do_sys_pwrite64 fs/read_write.c:712 [inline] __se_sys_pwrite64 fs/read_write.c:709 [inline] __x64_sys_pwrite64+0x1fd/0x250 fs/read_write.c:709 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x417167 Code: 12 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a1 18 00 00 c3 48 83 ec 08 e8 a7 f9 ff ff 48 89 04 24 49 89 ca b8 12 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 ed f9 ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fd8f04f3a20 EFLAGS: 00000293 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00000000000006b1 RCX: 0000000000417167 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000020018480 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 046a000000000000 R13: 0000000000000003 R14: 0000000000000003 R15: 000000002000a528