INFO: task kworker/u4:5:8713 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/u4:5 D26088 8713 2 0x80000000 Workqueue: writeback wb_workfn (flush-7:4) 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_balance_fs+0x709/0xd80 fs/f2fs/segment.c:512 f2fs_write_inode+0x500/0x600 fs/f2fs/inode.c:630 write_inode fs/fs-writeback.c:1244 [inline] __writeback_single_inode+0x733/0x11d0 fs/fs-writeback.c:1442 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_background_flush fs/fs-writeback.c:1890 [inline] wb_do_writeback fs/fs-writeback.c:1978 [inline] wb_workfn+0xacd/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: 2 locks held by kworker/u4:1/23: 4 locks held by kworker/u4:4/142: #0: 00000000e33d0f57 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 0000000043cbc365 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 0000000071228234 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 #3: 00000000900f71e7 (rcu_preempt_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x59/0x3e0 kernel/rcu/tree.c:3430 1 lock held by khungtaskd/1571: #0: 000000008983d450 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by systemd-udevd/4696: 1 lock held by in:imklog/7853: #0: 0000000015d70863 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 4 locks held by kworker/u4:5/8713: #0: 0000000031ab28a8 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000017c76d8 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000fe50b295 (&type->s_umount_key#58){++++}, at: trylock_super+0x1d/0x100 fs/super.c:412 #3: 00000000cbb6fd7e (&sbi->gc_mutex){+.+.}, at: f2fs_balance_fs+0x709/0xd80 fs/f2fs/segment.c:512 3 locks held by syz-executor.4/17745: ============================================= 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 10/26/2022 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: 17745 Comm: syz-executor.4 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:__lock_acquire+0x6fc/0x3ff0 kernel/locking/lockdep.c:3393 Code: 24 28 4c 89 54 24 20 e8 d2 e6 ff ff 4c 8b 54 24 20 85 c0 44 8b 4c 24 28 44 8b 44 24 30 0f 84 91 fa ff ff 48 c7 c2 60 37 24 8d <48> b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 14 02 48 c7 c0 60 RSP: 0018:ffff8880a3fff0c0 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000088 RCX: 1ffff11016538954 RDX: ffffffff8d243760 RSI: ffff8880b29c4a80 RDI: ffffffff8ce0dc10 RBP: ffff8880b29c4aa2 R08: 000000000000084f R09: 0000000000000003 R10: ffff8880b29c4a80 R11: 0000000000000000 R12: 00000000000c884f R13: ffff8880b29c4180 R14: ffff8880b29c4a98 R15: 0000000000000001 FS: 00007f8daa0a6700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c57fbf7988 CR3: 00000000a74a1000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_trylock include/linux/spinlock_api_smp.h:90 [inline] _raw_spin_trylock+0x60/0x70 kernel/locking/spinlock.c:128 ___ratelimit lib/ratelimit.c:42 [inline] ___ratelimit+0xd9/0x590 lib/ratelimit.c:28 f2fs_msg+0xd4/0x140 fs/f2fs/super.c:210 do_garbage_collect fs/f2fs/gc.c:1092 [inline] f2fs_gc+0x3072/0x8c90 fs/f2fs/gc.c:1196 f2fs_balance_fs+0x71a/0xd80 fs/f2fs/segment.c:513 f2fs_create+0x44d/0x930 fs/f2fs/namei.c:307 lookup_open+0x893/0x1a20 fs/namei.c:3235 do_last fs/namei.c:3327 [inline] path_openat+0x1094/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f8dabb340c9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8daa0a6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f8dabc53f80 RCX: 00007f8dabb340c9 RDX: 000000000000275a RSI: 0000000020000080 RDI: ffffffffffffff9c RBP: 00007f8dabb8fae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff172a4a8f R14: 00007f8daa0a6300 R15: 0000000000022000