INFO: task kworker/u4:7:9439 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:7 D26176 9439 2 0x80000000 Workqueue: writeback wb_workfn (flush-7:5) Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619 __mutex_lock_common kernel/locking/mutex.c:1016 [inline] __mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078 f2fs_sync_fs+0x278/0x530 fs/f2fs/super.c:1108 f2fs_balance_fs_bg+0x422/0xa40 fs/f2fs/segment.c:553 f2fs_write_node_pages+0x131/0xbb0 fs/f2fs/node.c:1927 do_writepages+0xe5/0x290 mm/page-writeback.c:2344 __writeback_single_inode+0x10c/0x11d0 fs/fs-writeback.c:1385 writeback_sb_inodes+0x537/0xef0 fs/fs-writeback.c:1647 __writeback_inodes_wb+0xc6/0x280 fs/fs-writeback.c:1716 wb_writeback+0x841/0xcc0 fs/fs-writeback.c:1822 wb_check_old_data_flush fs/fs-writeback.c:1924 [inline] wb_do_writeback fs/fs-writeback.c:1977 [inline] wb_workfn+0x8ba/0x1250 fs/fs-writeback.c:2006 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Showing all locks held in the system: 3 locks held by kworker/u4:4/996: 1 lock held by khungtaskd/1571: #0: 000000004f8d34bd (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by systemd-udevd/4697: 1 lock held by in:imklog/7801: #0: 000000003bb56ae1 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 2 locks held by agetty/8027: #0: 00000000feae2467 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 0000000009d9c67a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154 4 locks held by kworker/u4:7/9439: #0: 000000007c2c97e1 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000002bb5ad45 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 000000003781ab09 (&type->s_umount_key#87){++++}, at: trylock_super+0x1d/0x100 fs/super.c:412 #3: 0000000034871bc2 (&sbi->gc_mutex){+.+.}, at: f2fs_sync_fs+0x278/0x530 fs/f2fs/super.c:1108 3 locks held by syz-executor.5/13635: 2 locks held by syz-executor.0/22066: #0: 000000003781ab09 (&type->s_umount_key#87){++++}, at: iterate_supers+0xdb/0x290 fs/super.c:631 #1: 000000009ee8d9d0 (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 000000009ee8d9d0 (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x180/0x9a0 fs/fs-writeback.c:2457 2 locks held by syz-executor.2/23174: 5 locks held by syz-executor.1/23178: 2 locks held by syz-executor.0/23212: #0: 00000000feae2467 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000c187bbd5 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock drivers/tty/tty_io.c:889 [inline] #1: 00000000c187bbd5 (&tty->atomic_write_lock){+.+.}, at: do_tty_write drivers/tty/tty_io.c:909 [inline] #1: 00000000c187bbd5 (&tty->atomic_write_lock){+.+.}, at: tty_write+0x28f/0x810 drivers/tty/tty_io.c:1044 2 locks held by syz-executor.3/23218: 2 locks held by syz-executor.4/23230: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1571 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4697 Comm: systemd-udevd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 RIP: 0010:match_held_lock kernel/locking/lockdep.c:3477 [inline] RIP: 0010:__lock_is_held+0xc7/0x160 kernel/locking/lockdep.c:3728 Code: af f7 ff ff 85 c0 75 2f 83 c5 01 41 39 af 80 08 00 00 7e 70 48 63 c5 48 8d 04 80 49 8d 1c c4 48 8d 7b 10 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 75 6e 4c 3b 73 10 75 95 83 7c 24 04 ff b8 01 00 00 RSP: 0018:ffff88809bfaf660 EFLAGS: 00000806 RAX: 1ffff110137f411d RBX: ffff88809bfa08d8 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff88809bfa08e8 RBP: 0000000000000002 R08: 0000000000000000 R09: ffffed101742455a R10: ffff8880ba122ad3 R11: 0000000000000000 R12: ffff88809bfa0888 R13: dffffc0000000000 R14: ffffffff89f69d00 R15: ffff88809bfa0000 FS: 00007f24755518c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558e218602b8 CR3: 000000009c361000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held_type+0x10d/0x210 kernel/locking/lockdep.c:3946 lock_is_held include/linux/lockdep.h:344 [inline] select_task_rq_fair+0x764/0x2750 kernel/sched/fair.c:6450 select_task_rq kernel/sched/core.c:1532 [inline] try_to_wake_up+0x4cd/0x1050 kernel/sched/core.c:2037 wake_up_worker kernel/workqueue.c:839 [inline] insert_work+0x28b/0x360 kernel/workqueue.c:1312 __queue_work+0x5cd/0x1100 kernel/workqueue.c:1464 queue_work_on+0x17e/0x1f0 kernel/workqueue.c:1489 queue_work include/linux/workqueue.h:512 [inline] call_usermodehelper_exec+0x1f0/0x4d0 kernel/umh.c:571 kobject_uevent_env+0xe9f/0x1480 lib/kobject_uevent.c:616 kobject_synth_uevent+0x700/0x820 lib/kobject_uevent.c:208 uevent_store+0x21/0x70 drivers/base/core.c:1257 dev_attr_store+0x56/0x80 drivers/base/core.c:966 sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:140 kernfs_fop_write+0x2b0/0x470 fs/kernfs/file.c:316 __vfs_write+0xf7/0x770 fs/read_write.c:485 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f24743c3970 Code: 73 01 c3 48 8b 0d 28 d5 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 99 2d 2c 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 7e 9b 01 00 48 89 04 24 RSP: 002b:00007ffd0ede6198 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00007f24743c3970 RDX: 0000000000000007 RSI: 0000558e218478a0 RDI: 000000000000000e RBP: 0000558e218478a0 R08: 0000558e21856e40 R09: 00007f24755518c0 R10: 0000558e21856b10 R11: 0000000000000246 R12: 0000000000000007 R13: 0000000000000001 R14: 0000558e21856d60 R15: 0000000000000007