syzbot


INFO: task hung in hfs_mdb_commit (2)

Status: upstream: reported on 2024/04/07 10:21
Reported-by: syzbot+e8f67c5a2ba608c1f263@syzkaller.appspotmail.com
First crash: 42d, last: 42d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in hfs_mdb_commit hfs C error done 25 111d 489d 26/26 fixed on 2024/03/20 11:33
linux-6.1 INFO: task hung in hfs_mdb_commit 1 362d 362d 0/3 auto-obsoleted due to no activity on 2023/08/31 05:50
linux-5.15 INFO: task hung in hfs_mdb_commit (2) 2 4d18h 41d 0/3 upstream: reported on 2024/04/08 12:18
linux-4.19 INFO: task hung in hfs_mdb_commit hfs C error 1 480d 480d 0/1 upstream: reported C repro on 2023/01/25 02:58
linux-5.15 INFO: task hung in hfs_mdb_commit 1 344d 344d 0/3 auto-obsoleted due to no activity on 2023/09/18 06:33

Sample crash report:
INFO: task kworker/1:5:4286 blocked for more than 143 seconds.
      Not tainted 6.1.84-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:5     state:D stack:0     pid:4286  ppid:2      flags:0x00000008
Workqueue: events_long flush_mdb
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0xee4/0x1c98 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 io_schedule+0x8c/0x188 kernel/sched/core.c:8786
 bit_wait_io+0x1c/0xac kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xcc/0x1e8 kernel/sched/wait_bit.c:90
 out_of_line_wait_on_bit_lock+0x194/0x21c kernel/sched/wait_bit.c:117
 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline]
 __lock_buffer+0x78/0xac fs/buffer.c:69
 lock_buffer include/linux/buffer_head.h:397 [inline]
 hfs_mdb_commit+0x140/0xf2c fs/hfs/mdb.c:271
 flush_mdb+0x6c/0x9c fs/hfs/super.c:66
 process_one_work+0x7ac/0x1404 kernel/workqueue.c:2292
 worker_thread+0x8e4/0xfec kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015a14e70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015a15670 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
 #0: ffff800015a14ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
1 lock held by klogd/3831:
2 locks held by getty/3989:
 #0: ffff0000d7ee0098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001bcd02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2188
1 lock held by syz-executor.0/4238:
2 locks held by kworker/1:5/4286:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff80001eb67c20 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267

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Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/07 10:20 linux-6.1.y 347385861c50 ca620dd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in hfs_mdb_commit
* Struck through repros no longer work on HEAD.