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: 236d, last: 2d10h
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 1964d 1969d 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 1385d 1383d 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 3019 23d 965d 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 1597 44d 952d 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 617d 617d 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 1174d 1174d 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 1796d 1890d 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 821d 1210d 25/29 fixed on 2024/01/30 15:47

Sample crash report:
INFO: task syz-executor:5762 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:21704 pid:5762  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 gfs2_gl_hash_clear+0x1b4/0x450 fs/gfs2/glock.c:2256
 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+0x43b/0x4d0 fs/namespace.c:1259
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 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+0xee/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+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f14f699d9d7
RSP: 002b:00007fff7ca1a338 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007f14f699d9d7
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007fff7ca1b4e0
RBP: 00007f14f6a32050 R08: 00000000000105a0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000202 R12: 00007fff7ca1b4e0
R13: 00007f14f6a32050 R14: 00005555767a04e8 R15: 00007fff7ca1c5b0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8d132060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d132060 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d132060 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/u4:5/987:
 #0: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa9/0x140 kernel/sched/core.c:567
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2176/0x45a0 kernel/sched/core.c:6695
2 locks held by getty/5528:
 #0: ffff88802db3c0a0 (&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+0x433/0x1390 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5762:
 #0: ffff88806c4800e0 (&type->s_umount_key#98){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88806c4800e0 (&type->s_umount_key#98){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88806c4800e0 (&type->s_umount_key#98){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
3 locks held by kworker/0:14/8579:
 #0: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa9/0x140 kernel/sched/core.c:567
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2176/0x45a0 kernel/sched/core.c:6695
 #2: ffff8880b8e43c18 (&ACCESS_PRIVATE(sdp, lock)){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline]
 #2: ffff8880b8e43c18 (&ACCESS_PRIVATE(sdp, lock)){..-.}-{2:2}, at: srcu_invoke_callbacks+0x31e/0x460 kernel/rcu/srcutree.c:1749
2 locks held by udevd/9515:
 #0: ffff888148cc63b0 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:814 [inline]
 #0: ffff888148cc63b0 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: blkdev_read_iter+0x32f/0x480 block/fops.c:743
 #1: ffff888148cc6540 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:859 [inline]
 #1: ffff888148cc6540 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0xdc/0x770 mm/readahead.c:225
5 locks held by dhcpcd-run-hook/10981:

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

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 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 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+0xf3d/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: 10938 Comm: syz.2.1039 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:check_preemption_disabled+0x18/0x110 lib/smp_processor_id.c:14
Code: 80 85 1c 8b eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 <65> 8b 05 5d 8c 7e 75 65 8b 0d 52 8c 7e 75 f7 c1 ff ff ff 7f 74 1f
RSP: 0018:ffffc900046cf2e8 EFLAGS: 00000086
RAX: ce6bb50c68438e00 RBX: ffff888028fbe4dc RCX: ce6bb50c68438e00
RDX: 0000000000000000 RSI: ffffffff8acad640 RDI: ffffffff8b1c85a0
RBP: ffffc900046cf430 R08: ffffffff8e8aeeef R09: 1ffffffff1d15ddd
R10: dffffc0000000000 R11: fffffbfff1d15dde R12: ffffffff8430d91f
R13: dffffc0000000000 R14: ffff888028fbda00 R15: 1ffff920008d9e70
FS:  00007fc96612e6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559233c51950 CR3: 0000000068e0c000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 lockdep_recursion_inc kernel/locking/lockdep.c:462 [inline]
 lock_release+0x15c/0x8c0 kernel/locking/lockdep.c:5773
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x71/0x120 kernel/locking/spinlock.c:194
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x51f/0x540 lib/debugobjects.c:1020
 free_pages_prepare mm/page_alloc.c:1187 [inline]
 free_unref_page_prepare+0x1da/0x8c0 mm/page_alloc.c:2365
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2504
 release_pages+0x1f7a/0x2200 mm/swap.c:1022
 __folio_batch_release+0x71/0xe0 mm/swap.c:1042
 folio_batch_release include/linux/pagevec.h:83 [inline]
 shmem_undo_range+0x630/0x1b20 mm/shmem.c:1026
 shmem_truncate_range mm/shmem.c:1135 [inline]
 shmem_evict_inode+0x245/0x9e0 mm/shmem.c:1264
 evict+0x4ca/0x8d0 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfe/0x1e0 fs/dcache.c:918
 __fput+0x5e5/0x970 fs/file_table.c:392
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 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+0xee/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+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc96519c42b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007fc96612de00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: ffffffffffffffff RCX: 00007fc96519c42b
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000d
R13: 00007fc96612dea0 R14: 00000000000055ae R15: 0000200000000080
 </TASK>

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/20 23:02 linux-6.6.y 4fc00fe35d46 ac6f1dff .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2026/01/19 07:22 linux-6.6.y cbb31f77b879 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2026/01/19 07:15 linux-6.6.y cbb31f77b879 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
2026/01/19 07:14 linux-6.6.y cbb31f77b879 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in gfs2_gl_hash_clear
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.