syzbot


INFO: task hung in hfs_mdb_commit (2)

Status: upstream: reported C repro on 2024/04/08 12:18
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+fe315034987e78af3fc1@syzkaller.appspotmail.com
First crash: 145d, last: 103d
Fix bisection: failed (error log, bisect log)
  
Bug presence (1)
Date Name Commit Repro Result
2024/05/20 upstream (ToT) eb6a9339efeb C [report] INFO: task hung in hfs_mdb_commit
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 215d 593d 25/27 fixed on 2024/03/20 11:33
linux-6.1 INFO: task hung in hfs_mdb_commit 1 466d 466d 0/3 auto-obsoleted due to no activity on 2023/08/31 05:50
linux-4.19 INFO: task hung in hfs_mdb_commit hfs C error 1 584d 584d 0/1 upstream: reported C repro on 2023/01/25 02:58
linux-5.15 INFO: task hung in hfs_mdb_commit 1 448d 448d 0/3 auto-obsoleted due to no activity on 2023/09/18 06:33
linux-6.1 INFO: task hung in hfs_mdb_commit (2) 1 146d 146d 0/3 auto-obsoleted due to no activity on 2024/07/16 10:21

Sample crash report:
INFO: task kworker/0:2:1952 blocked for more than 143 seconds.
      Not tainted 5.15.159-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D stack:    0 pid: 1952 ppid:     2 flags:0x00000008
Workqueue: events_long flush_mdb
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xf10/0x1e48 kernel/sched/core.c:6376
 schedule+0x11c/0x1c8 kernel/sched/core.c:6459
 io_schedule+0x8c/0x194 kernel/sched/core.c:8484
 bit_wait_io+0x1c/0xac kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xcc/0x1f0 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+0x80/0xc0 fs/buffer.c:69
 lock_buffer include/linux/buffer_head.h:402 [inline]
 hfs_mdb_commit+0xa20/0xfc0 fs/hfs/mdb.c:325
 flush_mdb+0x6c/0x9c fs/hfs/super.c:66
 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
 worker_thread+0x910/0x1034 kernel/workqueue.c:2457
 kthread+0x37c/0x45c kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffff800014b214a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:311
2 locks held by kworker/0:2/1952:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800022277c00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
2 locks held by getty/3723:
 #0: ffff0000d2f61098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001a3db2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1204 drivers/tty/n_tty.c:2158
1 lock held by udevd/3990:

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


Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/20 11:32 linux-5.15.y 83655231580b c0f1611a .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 INFO: task hung in hfs_mdb_commit
2024/05/15 07:35 linux-5.15.y 284087d4f7d5 fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
2024/04/08 12:18 linux-5.15.y 9465fef4ae35 ca620dd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
* Struck through repros no longer work on HEAD.