syzbot


INFO: task hung in jfs_flush_journal (2)

Status: upstream: reported on 2025/06/11 18:53
Reported-by: syzbot+35a98e8b9200b5a21f63@syzkaller.appspotmail.com
First crash: 2d18h, last: 2d18h
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in jfs_flush_journal jfs 1 969d 969d 0/28 auto-obsoleted due to no activity on 2023/01/17 08:27
upstream INFO: task hung in jfs_flush_journal (3) jfs 4 735d 780d 0/28 auto-obsoleted due to no activity on 2023/09/08 02:21
upstream INFO: task hung in jfs_flush_journal (2) jfs 1 870d 870d 0/28 auto-obsoleted due to no activity on 2023/04/25 22:54
linux-6.1 INFO: task hung in jfs_flush_journal 1 304d 304d 0/3 auto-obsoleted due to no activity on 2024/11/22 04:48
upstream INFO: task hung in jfs_flush_journal (4) jfs 43 37d 268d 0/28 upstream: reported on 2024/09/19 03:31
linux-4.19 INFO: task hung in jfs_flush_journal jfs 1 881d 881d 0/1 upstream: reported on 2023/01/14 13:39
linux-5.15 INFO: task hung in jfs_flush_journal 1 749d 749d 0/3 auto-obsoleted due to no activity on 2023/09/03 18:59

Sample crash report:
INFO: task syz.0.280:5098 blocked for more than 143 seconds.
      Not tainted 6.1.141-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.280       state:D stack:27304 pid:5098  ppid:4254   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 jfs_flush_journal+0x708/0xea0 fs/jfs/jfs_logmgr.c:1564
 jfs_sync_fs+0x79/0xa0 fs/jfs/super.c:684
 sync_filesystem+0x1be/0x220 fs/sync.c:66
 jfs_remount+0xe8/0x5a0 fs/jfs/super.c:432
 reconfigure_super+0x219/0x880 fs/super.c:977
 do_remount fs/namespace.c:2710 [inline]
 path_mount+0xdfd/0x1010 fs/namespace.c:3376
 do_mount fs/namespace.c:3397 [inline]
 __do_sys_mount fs/namespace.c:3605 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3582
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f653c58e929
RSP: 002b:00007f653d33d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f653c7b6080 RCX: 00007f653c58e929
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007f653c610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002236824 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f653c7b6080 R15: 00007ffd0b3cb058
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92b430 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8c92bc50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4016:
 #0: ffff88814ce8d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000326b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by syz.0.280/5098:
 #0: ffff8880503d00e0 (&type->s_umount_key#81){++++}-{3:3}, at: do_remount fs/namespace.c:2707 [inline]
 #0: ffff8880503d00e0 (&type->s_umount_key#81){++++}-{3:3}, at: path_mount+0xdbb/0x1010 fs/namespace.c:3376
2 locks held by kworker/1:15/5203:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003637d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by kworker/0:15/5403:
 #0: ffff888017470938
 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004937d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by syz-executor/6280:
 #0: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x346/0x830 kernel/rcu/tree_exp.h:962
3 locks held by kworker/u4:8/6351:
1 lock held by syz.2.914/7015:
 #0: ffff8880503d00e0 (&type->s_umount_key#81){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
2 locks held by syz.4.1212/8116:
2 locks held by dhcpcd/8132:
 #0: ffff8880742f3210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff8880742f3210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
 #0: ffff8880742f3210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1400
 #1: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffffffff8c930778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2922 Comm: kworker/u4:6 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2c/0x60 kernel/kcov.c:216
Code: 04 24 65 48 8b 0d c4 98 81 7e 65 8b 15 c5 98 81 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48
RSP: 0018:ffffc9000cc07b48 EFLAGS: 00000246
RAX: ffffffff8602f682 RBX: 0000000000000000 RCX: ffff88802f5c8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8881447c1a48 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52001980f58 R11: 1ffff92001980f58 R12: dffffc0000000000
R13: ffff88801eab70a8 R14: ffff8880750f5608 R15: 0000000000000010
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffedba25b48 CR3: 00000000752db000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:792 [inline]
 nsim_dev_trap_report_work+0x782/0xaf0 drivers/net/netdevsim/dev.c:851
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/11 18:52 linux-6.1.y 58485ff1a74f 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in jfs_flush_journal
* Struck through repros no longer work on HEAD.