syzbot


INFO: task hung in gfs2_gl_hash_clear

Status: upstream: reported on 2025/07/29 17:31
Reported-by: syzbot+b4867545efb9c6e2b0e6@syzkaller.appspotmail.com
First crash: 169d, last: 39d
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in gfs2_gl_hash_clear gfs2 1 156 1896d 1901d 0/29 auto-closed as invalid on 2021/02/02 22:47
upstream INFO: task hung in gfs2_gl_hash_clear (2) gfs2 1 1 1317d 1316d 0/29 auto-closed as invalid on 2022/09/04 20:20
linux-5.15 INFO: task hung in gfs2_gl_hash_clear origin:lts-only 1 C inconclusive 2944 10m 897d 0/3 upstream: reported C repro on 2023/08/01 02:35
linux-6.1 INFO: task hung in gfs2_gl_hash_clear missing-backport origin:lts-only 1 C done 1596 19d 885d 0/3 upstream: reported C repro on 2023/08/13 12:57
upstream INFO: task hung in gfs2_gl_hash_clear (4) gfs2 1 1 550d 550d 0/29 auto-obsoleted due to no activity on 2024/10/11 16:48
linux-4.19 INFO: task hung in gfs2_gl_hash_clear gfs2 1 1 1106d 1106d 0/1 upstream: reported on 2023/01/04 01:01
upstream INFO: task can't die in gfs2_gl_hash_clear (2) gfs2 1 3 1728d 1822d 0/29 auto-closed as invalid on 2021/07/21 03:15
upstream INFO: task hung in gfs2_gl_hash_clear (3) gfs2 1 C error done 80 753d 1142d 25/29 fixed on 2024/01/30 15:47

Sample crash report:
INFO: task syz-executor:5783 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:22024 pid:5783  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
 gfs2_gl_hash_clear+0x1a2/0x430 fs/gfs2/glock.c:2238
 gfs2_put_super+0x8bb/0x930 fs/gfs2/super.c:650
 generic_shutdown_super+0x134/0x2b0 fs/super.c:693
 kill_block_super+0x44/0x90 fs/super.c:1660
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x429/0x4c0 fs/namespace.c:1259
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd9f9d90a77
RSP: 002b:00007ffe3dab73c8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007fd9f9d90a77
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffe3dab8570
RBP: 00007fd9f9e13d7d R08: 000055557ab2d643 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000202 R12: 00007ffe3dab8570
R13: 00007fd9f9e13d7d R14: 000055557ab124a8 R15: 00007ffe3dab9640
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u4:1/12:
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90000117d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90000117d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/1:2/788:
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90003c87d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90003c87d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
5 locks held by kworker/u4:7/1093:
 #0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc9000491fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc9000491fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfaf8d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x136/0xb90 net/core/net_namespace.c:606
 #3: ffff88814d603250 (&devlink->lock_key#60){+.+.}-{3:3}, at: devl_lock net/devlink/core.c:60 [inline]
 #3: ffff88814d603250 (&devlink->lock_key#60){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0xe1/0x340 net/devlink/core.c:285
 #4: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:335 [inline]
 #4: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: nsim_create+0x384/0x4a0 drivers/net/netdevsim/netdev.c:401
3 locks held by kworker/u4:9/1130:
 #0: ffff88802c878d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff88802c878d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004a8fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004a8fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x14e0 net/ipv6/addrconf.c:4158
2 locks held by getty/5551:
 #0: ffff88814ca430a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000328b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5783:
 #0: ffff88801f2960e0 (&type->s_umount_key#72){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88801f2960e0 (&type->s_umount_key#72){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88801f2960e0 (&type->s_umount_key#72){++++}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
3 locks held by kworker/1:7/5859:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004aafd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004aafd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffff88805dbae240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26c/0x3170 drivers/net/netdevsim/fib.c:1491
2 locks held by kworker/0:7/6795:
 #0: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x20ee/0x44d0 kernel/sched/core.c:6694
1 lock held by syz-executor/7524:
 #0: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 #0: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
1 lock held by syz-executor/7549:
 #0: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 #0: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
2 locks held by syz-executor/7574:
 #0: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 #0: ffffffff8dfbc708 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
 #1: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #1: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1130 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
RIP: 0010:rcu_is_watching+0x6/0xb0 kernel/rcu/tree.c:699
Code: eb 99 e8 2d 83 ff 08 48 c7 c7 80 67 d3 8c 4c 89 f6 e8 8e 6a e2 02 e9 53 ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 57 <41> 56 53 65 ff 05 f8 1b 94 7e e8 0b 99 ff 08 89 c3 83 f8 08 73 60
RSP: 0018:ffffc90004a8fa30 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8166f9bc
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a93e8
RBP: ffffc90004a8fb48 R08: ffffffff8e4a93ef R09: 1ffffffff1c9527d
R10: dffffc0000000000 R11: fffffbfff1c9527e R12: 1ffff92000951f54
R13: ffffffff8cd2ff20 R14: 0000000000000001 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f01b8462a10 CR3: 000000000cb30000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xcb/0x410 kernel/locking/lockdep.c:5725
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xef/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/05 23:46 linux-6.6.y 4791134e4aeb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/11/03 16:29 linux-6.6.y 0a805b6ea8cd 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/10/21 14:50 linux-6.6.y f231f248323d 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/10/20 12:31 linux-6.6.y f231f248323d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/10/04 16:09 linux-6.6.y f34f16e5c632 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/18 00:42 linux-6.6.y bb9c90ab9c5a 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/11 13:09 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/10 18:03 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/10 17:56 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/10 17:44 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/10 17:42 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/06 20:00 linux-6.6.y 3a8ababb8b6a ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/08/06 19:46 linux-6.6.y 3a8ababb8b6a ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/07/30 12:53 linux-6.6.y dbcb8d8e4163 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/07/30 11:56 linux-6.6.y dbcb8d8e4163 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2025/07/29 17:31 linux-6.6.y dbcb8d8e4163 c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
* Struck through repros no longer work on HEAD.