INFO: task kworker/u4:6:9477 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/u4:6 D25496 9477 2 0x80000000 Workqueue: writeback wb_workfn (flush-7:1) 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 caif:caif_disconnect_client(): nothing to disconnect __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: 1 lock held by khungtaskd/1570: #0: 00000000bb71efe9 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by systemd-udevd/4698: 1 lock held by in:imklog/7812: #0: 0000000002983fb5 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 caif:caif_disconnect_client(): nothing to disconnect 4 locks held by kworker/u4:6/9477: #0: 00000000eff01ecf ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 0000000073eaf905 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 netlink: 52 bytes leftover after parsing attributes in process `syz-executor.3'. #2: 00000000e64f566e (&type->s_umount_key#96){++++}, at: trylock_super+0x1d/0x100 fs/super.c:412 #3: 00000000c2b6c259 (&sbi->gc_mutex){+.+.}, at: f2fs_balance_fs+0x709/0xd80 fs/f2fs/segment.c:512 4 locks held by syz-executor.1/30354: 3 locks held by syz-executor.2/8510: #0: 0000000094190f1e (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 0000000094190f1e (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598 #1: 0000000039d28997 (sk_lock-AF_CAIF){+.+.}, at: lock_sock include/net/sock.h:1512 [inline] #1: 0000000039d28997 (sk_lock-AF_CAIF){+.+.}, at: caif_release+0xe9/0x350 net/caif/caif_socket.c:922 #2: 0000000018fefeeb (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #2: 0000000018fefeeb (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1570 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: 20875 Comm: kworker/u4:0 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: bat_events batadv_nc_worker RIP: 0010:preempt_count_sub+0x0/0x150 kernel/sched/core.c:3262 Code: 4c 8b 45 c8 48 8b 55 d0 e9 0f fc ff ff 89 4d d0 e8 15 f5 56 00 8b 4d d0 e9 88 fe ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 <48> c7 c0 60 37 24 8d 53 89 fb 48 ba 00 00 00 00 00 fc ff df 48 89 RSP: 0018:ffff8881f10c7c18 EFLAGS: 00000046 RAX: 0000000000000007 RBX: 0000000000000201 RCX: 1ffffffff1a486ec RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000200 RBP: ffffffff87d8bc2d R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000000 R12: ffff888044aba240 R13: ffffffff87d8d930 R14: 000000000000003b R15: ffff8880423f0dc0 FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fce85310262 CR3: 00000000a792e000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __local_bh_enable_ip+0x138/0x270 kernel/softirq.c:182 spin_unlock_bh include/linux/spinlock.h:374 [inline] batadv_nc_purge_paths+0x22d/0x310 net/batman-adv/network-coding.c:482 batadv_nc_worker+0x731/0xd50 net/batman-adv/network-coding.c:733 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