syzbot


INFO: task hung in hfsplus_find_init

Status: upstream: reported C repro on 2025/12/01 22:56
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+8c954c4ddd1a7be135e8@syzkaller.appspotmail.com
First crash: 200d, last: 4d15h
Fix bisection: failed (error log, bisect log)
  
Bug presence (1)
Date Name Commit Repro Result
2025/12/02 upstream (ToT) 4a26e7032d7d C [report] INFO: task hung in corrupted
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in hfsplus_find_init hfs 1 C error done 1 912d 1006d 25/29 fixed on 2024/01/31 13:17
upstream INFO: task hung in hfsplus_find_init (3) prio:high hfs 1 C error error 43 43d 322d 0/29 upstream: reported C repro on 2025/08/01 17:38
upstream INFO: task hung in hfsplus_find_init (2) hfs 1 1 631d 631d 0/29 auto-obsoleted due to no activity on 2024/12/25 06:58
linux-6.6 INFO: task hung in hfsplus_find_init origin:upstream 1 C error 17 168d 186d 0/2 upstream: reported C repro on 2025/12/15 15:07
linux-6.1 INFO: task hung in hfsplus_find_init origin:upstream missing-backport 1 C error 13 26d 174d 0/3 upstream: reported C repro on 2025/12/27 18:45
Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/05/23 23:30 17m retest repro linux-5.15.y report log
2026/05/23 23:30 18m retest repro linux-5.15.y report log
2026/05/23 23:30 20m retest repro linux-5.15.y report log
2026/05/23 23:30 18m retest repro linux-5.15.y report log
2026/05/09 22:04 23m retest repro linux-5.15.y report log
2026/04/14 08:41 18m retest repro linux-5.15.y error
2026/03/31 06:39 13m retest repro linux-5.15.y report log
2026/03/31 06:39 13m retest repro linux-5.15.y report log
2026/03/31 06:39 13m retest repro linux-5.15.y report log
2026/03/31 06:39 19m retest repro linux-5.15.y report log

Sample crash report:
INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:23696 pid:    9 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn
 (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xcfc/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
 hfsplus_cat_write_inode+0x21c/0x870 fs/hfsplus/inode.c:613
 write_inode fs/fs-writeback.c:1505 [inline]
 __writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1715
 writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
 wb_writeback+0x46f/0xbe0 fs/fs-writeback.c:2116
 wb_check_background_flush fs/fs-writeback.c:2182 [inline]
 wb_do_writeback fs/fs-writeback.c:2270 [inline]
 wb_workfn+0xbd6/0xf20 fs/fs-writeback.c:2298
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
 #0: ffff8880191d0938
 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc90000ce7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff88807b18a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807b73e0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
1 lock held by khungtaskd/27:
 #0: ffffffff8c31f360 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
 #0: ffff8880191d0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000174fd00
 (
(work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: 
ffff888022f3c0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff888022f380b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
2 locks held by kworker/u4:3/490:
 #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000333fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
3 locks held by kworker/1:2/1324:
4 locks held by kworker/u4:4/3067:
 #0: ffff8880191d0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000d44fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: 
ffff888074b5c0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807afaa0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
2 locks held by getty/3946:
 #0: ffff88802c8fc098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
3 locks held by kworker/1:5/4316:
3 locks held by kworker/1:7/4319:
 #0: 
ffff8880b913a358
 (
&rq->__lock
){-.-.}-{2:2}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: 
ffffc9000304fd00
 ((gc_work).work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: __rq_lockp kernel/sched/sched.h:1191 [inline]
 #2: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: finish_lock_switch+0x60/0x280 kernel/sched/core.c:4801
7 locks held by syz.0.17/4353:
4 locks held by kworker/u4:5/4372:
 #0: 
ffff8880191d0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: 
ffffc900031efd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: 
ffff88807d9620e0
 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: 
ffff88807e2540b0
 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u4:6/4373:
 #0: 
ffff8880191d0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900031ffd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff888020fd20e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff888020fd60b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u4:7/4374:
 #0: 
ffff8880191d0938
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: 
ffffc9000320fd00
 (
(work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff88807deec0e0
 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88805a17c0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
7 locks held by syz.1.18/4391:
10 locks held by syz.2.19/4408:
7 locks held by syz.3.20/4430:
7 locks held by syz.4.21/4455:
3 locks held by kworker/u4:9/4464:
7 locks held by syz.5.22/4486:
1 lock held by syz-executor/4488:


Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/15 09:00 linux-5.15.y dc027a595035 1d2f3589 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/03 15:04 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/03 11:25 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/03 07:53 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/03 04:27 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/03 00:46 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/02 21:08 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/02 17:44 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/02 14:14 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/02 09:16 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/02 05:50 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/02 02:25 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2026/02/21 17:21 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2026/01/02 16:40 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2026/01/02 16:38 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2026/01/01 07:00 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
2025/12/01 22:55 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfsplus_find_init
* Struck through repros no longer work on HEAD.