INFO: task kworker/u4:3:762 blocked for more than 140 seconds. Not tainted 4.19.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:3 D12360 762 2 0x80080000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x2e8/0x8f0 kernel/sched/core.c:3473 schedule+0x31/0x90 kernel/sched/core.c:3517 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3575 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x224/0x730 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 jfs_commit_inode+0x6a/0x130 fs/jfs/inode.c:114 jfs_write_inode+0x27/0x60 fs/jfs/inode.c:144 write_inode fs/fs-writeback.c:1183 [inline] __writeback_single_inode+0x2fb/0x4d0 fs/fs-writeback.c:1382 writeback_sb_inodes+0x226/0x590 fs/fs-writeback.c:1587 __writeback_inodes_wb+0x62/0xb0 fs/fs-writeback.c:1656 wb_writeback+0x377/0x3c0 fs/fs-writeback.c:1765 wb_check_old_data_flush fs/fs-writeback.c:1867 [inline] wb_do_writeback fs/fs-writeback.c:1920 [inline] wb_workfn+0x405/0x520 fs/fs-writeback.c:1949 process_one_work+0x255/0x4e0 kernel/workqueue.c:2153 worker_thread+0x2f/0x320 kernel/workqueue.c:2296 kthread+0x119/0x130 kernel/kthread.c:246 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:413 Showing all locks held in the system: 4 locks held by kworker/u4:3/762: #0: 00000000ede7d020 ((wq_completion)"writeback"){....}, at: wake_up_worker kernel/workqueue.c:838 [inline] #0: 00000000ede7d020 ((wq_completion)"writeback"){....}, at: process_one_work+0x1b1/0x4e0 kernel/workqueue.c:2116 #1: 00000000df1cc67a ((work_completion)(&(&wb->dwork)->work)){....}, at: wake_up_worker kernel/workqueue.c:838 [inline] #1: 00000000df1cc67a ((work_completion)(&(&wb->dwork)->work)){....}, at: process_one_work+0x1b1/0x4e0 kernel/workqueue.c:2116 #2: 0000000094062313 (&type->s_umount_key#42){....}, at: trylock_super+0x16/0x50 fs/super.c:412 #3: 00000000a20a36c2 (&jfs_ip->commit_mutex){....}, at: jfs_commit_inode+0x6a/0x130 fs/jfs/inode.c:114 1 lock held by khungtaskd/783: #0: 00000000bd52af17 (rcu_read_lock){....}, at: debug_show_all_locks+0x23/0x10d kernel/locking/lockdep.c:4435 2 locks held by getty/2869: #0: 00000000be83da10 (&tty->ldisc_sem){....}, at: ldsem_down_read+0xe/0x10 drivers/tty/tty_ldsem.c:353 #1: 00000000bc775851 (&ldata->atomic_read_lock){....}, at: n_tty_read+0xbc/0x860 drivers/tty/n_tty.c:2140 4 locks held by syz-executor.0/3818: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 783 Comm: khungtaskd Not tainted 4.19.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x89/0xba lib/dump_stack.c:113 nmi_cpu_backtrace.cold.0+0x14/0x53 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xc5/0xce lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0x2c7/0x400 kernel/hung_task.c:265 kthread+0x119/0x130 kernel/kthread.c:246 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3818 Comm: syz-executor.0 Not tainted 4.19.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:dtSplitRoot+0x250/0x470 fs/jfs/jfs_dtree.c:1986 Code: 20 39 c6 7f ee c6 02 ff 41 0f be 87 d3 fe ff ff 83 f8 ff 0f 84 da 01 00 00 41 88 46 13 48 98 48 c1 e0 05 49 8d 14 06 0f be 02 <83> f8 ff 75 ee 88 0a 41 0f b6 87 d2 fe ff ff 29 c8 41 02 46 14 41 RSP: 0018:ffffc900013a7ab0 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000080 RCX: 000000000000000d RDX: ffff8801335100c0 RSI: 0000000000000080 RDI: ffff880133510120 RBP: ffffc900013a7b48 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff880135f09580 R13: ffffc900013a7c34 R14: ffff880133510000 R15: ffff880134b42228 FS: 00007f77a6c9c6c0(0000) GS:ffff88013ba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f953b60f000 CR3: 0000000133516000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dtSplitUp+0x5cd/0x1710 fs/jfs/jfs_dtree.c:998 dtInsert+0x204/0x230 fs/jfs/jfs_dtree.c:876 jfs_mkdir+0x282/0x370 fs/jfs/namei.c:282 vfs_mkdir+0x101/0x1a0 fs/namei.c:3817 do_mkdirat+0xe5/0x110 fs/namei.c:3840 __do_sys_mkdirat fs/namei.c:3851 [inline] __se_sys_mkdirat fs/namei.c:3849 [inline] __x64_sys_mkdirat+0x15/0x20 fs/namei.c:3849 do_syscall_64+0x63/0x160 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f77a71185e7 Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f77a6c9bee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f77a71185e7 RDX: 00000000000001ff RSI: 0000000020000500 RDI: 00000000ffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000500 R13: 00007f77a6c9bf40 R14: 0000000000000000 R15: 0000000000000000