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: 555d, last: 3d06h
Fix bisection: failed (error log, bisect log)
  
Bug presence (1)
Date Name Commit Repro Result
2024/10/29 upstream (ToT) e42b1a9a2557 C [report] INFO: task hung in hfs_mdb_commit
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in hfs_mdb_commit hfs 1 C error done 25 625d 1003d 25/29 fixed on 2024/03/20 11:33
linux-6.1 INFO: task hung in hfs_mdb_commit 1 1 877d 877d 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 1 C error 1 995d 995d 0/1 upstream: reported C repro on 2023/01/25 02:58
linux-6.1 INFO: task hung in hfs_mdb_commit (3) 1 1 245d 245d 0/3 auto-obsoleted due to no activity on 2025/05/23 22:52
linux-5.15 INFO: task hung in hfs_mdb_commit 1 1 859d 859d 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 1 556d 556d 0/3 auto-obsoleted due to no activity on 2024/07/16 10:21
linux-6.6 INFO: task hung in hfs_mdb_commit 1 1 47d 47d 0/2 upstream: reported on 2025/08/29 18:32
upstream INFO: task hung in hfs_mdb_commit (2) hfs 1 1 477d 477d 0/29 auto-obsoleted due to no activity on 2024/09/23 18:09
upstream INFO: task hung in hfs_mdb_commit (3) hfs 1 C error done 10 45d 124d 0/29 upstream: reported C repro on 2025/06/13 11:04
Last patch testing requests (7)
Created Duration User Patch Repo Result
2025/10/13 01:58 44m retest repro linux-5.15.y report log
2025/08/27 23:15 18m retest repro linux-5.15.y report log
2025/07/30 07:12 13m retest repro linux-5.15.y report log
2025/06/16 12:23 3h10m (2) retest repro linux-5.15.y report log
2025/05/20 18:19 23m retest repro linux-5.15.y report log
2025/04/06 16:59 13m retest repro linux-5.15.y report log
2025/03/08 06:49 13m retest repro linux-5.15.y report log

Sample crash report:
INFO: task kworker/1:2:2239 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2     state:D stack:24040 pid: 2239 ppid:     2 flags:0x00004000
Workqueue: events_long flush_mdb
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xbc/0x1a0 kernel/sched/wait_bit.c:90
 out_of_line_wait_on_bit_lock+0x11f/0x160 kernel/sched/wait_bit.c:117
 lock_buffer include/linux/buffer_head.h:402 [inline]
 hfs_mdb_commit+0x113/0x1110 fs/hfs/mdb.c:271
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz-executor:4308 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21856 pid: 4308 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xbc/0x1a0 kernel/sched/wait_bit.c:90
 out_of_line_wait_on_bit_lock+0x11f/0x160 kernel/sched/wait_bit.c:117
 lock_buffer include/linux/buffer_head.h:402 [inline]
 hfs_mdb_commit+0xadf/0x1110 fs/hfs/mdb.c:325
 hfs_sync_fs+0x11/0x20 fs/hfs/super.c:35
 sync_filesystem+0xe6/0x220 fs/sync.c:56
 generic_shutdown_super+0x6b/0x300 fs/super.c:448
 kill_block_super+0x7c/0xe0 fs/super.c:1427
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x418/0x4d0 fs/namespace.c:1139
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f91362561f7
RSP: 002b:00007ffd23346418 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f91362d7d7d RCX: 00007f91362561f7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd233464d0
RBP: 00007ffd233464d0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd23347560
R13: 00007f91362d7d7d R14: 0000000000024de0 R15: 00007ffd233475a0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/1:2/2239:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000614fd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by getty/3946:
 #0: ffff88802bc72098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:11/4263:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002fcfd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/1:3/4265:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002f4fd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/1:4/4280:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002fefd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by syz-executor/4308:
 #0: ffff88807bc9e0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
2 locks held by kworker/0:17/4329:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900030efd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/0:18/4330:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900030ffd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/0:21/4336:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000312fd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by syz-executor/4384:
 #0: ffff88805d3620e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
2 locks held by kworker/1:5/4402:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900032efd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by syz-executor/4409:
 #0: ffff8880234860e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
1 lock held by syz-executor/4430:
 #0: ffff88807a4ee0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
2 locks held by kworker/1:6/4445:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900034dfd00 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by syz-executor/4452:
 #0: ffff88807b18e0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
1 lock held by syz-executor/4485:
 #0: ffff888078bc20e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
1 lock held by syz-executor/4512:
 #0: ffff8880218a80e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
1 lock held by syz-executor/4539:
 #0: ffff88805c8220e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
1 lock held by syz-executor/4568:
 #0: ffff88805c8040e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
2 locks held by syz-executor/4602:
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238048 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
 #1: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 719 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: phy15 ieee80211_iface_work
RIP: 0010:__hlist_del include/linux/list.h:858 [inline]
RIP: 0010:hlist_del include/linux/list.h:870 [inline]
RIP: 0010:__alloc_object lib/debugobjects.c:217 [inline]
RIP: 0010:alloc_object+0x11f/0x650 lib/debugobjects.c:230
Code: 08 48 89 df e8 02 fe dc fd 4c 89 23 4d 85 e4 74 27 49 83 c4 08 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 4c 89 e7 e8 d7 fd dc fd 49 89 1c 24 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc9000355f238 EFLAGS: 00000046
RAX: 1ffff1100b858c08 RBX: ffff8880b9137010 RCX: dffffc0000000000
RDX: ffffffff8a0c1ce0 RSI: ffffffff8a59a460 RDI: ffffffff8a59a420
RBP: ffff88805aaef070 R08: 0000000000000004 R09: 0000000000000003
R10: fffff520006abe34 R11: 1ffff920006abe34 R12: ffff88805c2c6040
R13: 1ffff1100b55de0f R14: 1ffff1100b55de0e R15: ffff88805aaef078
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5dcc599d68 CR3: 000000002a7f0000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lookup_object_or_alloc lib/debugobjects.c:591 [inline]
 debug_object_activate+0x139/0x480 lib/debugobjects.c:696
 debug_rcu_head_queue kernel/rcu/rcu.h:176 [inline]
 kvfree_call_rcu+0xb5/0x7c0 kernel/rcu/tree.c:3591
 cfg80211_update_known_bss+0x178/0xa20 net/wireless/scan.c:-1
 cfg80211_bss_update+0x15f/0x2250 net/wireless/scan.c:1836
 cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2555 [inline]
 cfg80211_inform_bss_frame_data+0x873/0x1f30 net/wireless/scan.c:2588
 ieee80211_bss_info_update+0x6c2/0xaa0 net/mac80211/scan.c:190
 ieee80211_rx_bss_info net/mac80211/ibss.c:1123 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x16d0/0x29c0 net/mac80211/ibss.c:1643
 ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
 ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/29 00:04 linux-5.15.y 43bb85222e53 001c9061 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
2024/10/28 09:35 linux-5.15.y 74cdd62cb470 65e8686b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
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
2025/01/12 08:24 linux-5.15.y 4735586da88e 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
2024/10/28 05:36 linux-5.15.y 74cdd62cb470 65e8686b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
2024/10/28 05:36 linux-5.15.y 74cdd62cb470 65e8686b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in hfs_mdb_commit
2024/10/22 13:34 linux-5.15.y 584a40a22cb9 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan 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.