syzbot


INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.

Status: upstream: reported on 2026/03/28 01:24
Subsystems: gfs2
[Documentation on labels]
Reported-by: syzbot+cbe76ae6ba264c7a9bb4@syzkaller.appspotmail.com
First crash: 28d, last: 7d15h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [gfs2?] INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds. 0 (1) 2026/03/28 01:24

Sample crash report:
INFO: task kworker/0:0H:11 blocked in I/O wait for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0H    state:D stack:26568 pid:11    tgid:11    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: gfs2-glock/syz:syz glock_work_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5354 [inline]
 __schedule+0x165c/0x5520 kernel/sched/core.c:6966
 __schedule_loop kernel/sched/core.c:7049 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7064
 io_schedule+0x7f/0xd0 kernel/sched/core.c:7891
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit_lock+0xec/0x4e0 kernel/sched/wait_bit.c:93
 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
 wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline]
 __lock_buffer fs/buffer.c:71 [inline]
 lock_buffer include/linux/buffer_head.h:432 [inline]
 discard_buffer fs/buffer.c:1496 [inline]
 block_invalidate_folio+0x370/0x730 fs/buffer.c:1553
 folio_invalidate mm/truncate.c:140 [inline]
 truncate_cleanup_folio+0xcb/0x190 mm/truncate.c:160
 truncate_inode_pages_range+0x2ce/0xe30 mm/truncate.c:404
 inode_go_inval+0x13c/0x360 fs/gfs2/glops.c:366
 do_xmote+0x289/0x760 fs/gfs2/glock.c:699
 glock_work_func+0x2a8/0x580 fs/gfs2/glock.c:1011
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz-executor:5838 blocked in I/O wait for more than 144 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:20312 pid:5838  tgid:5838  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5354 [inline]
 __schedule+0x165c/0x5520 kernel/sched/core.c:6966
 __schedule_loop kernel/sched/core.c:7049 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7064
 io_schedule+0x7f/0xd0 kernel/sched/core.c:7891
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit+0xb9/0x310 kernel/sched/wait_bit.c:52
 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 gfs2_evict_inode+0xbd2/0x12d0 fs/gfs2/super.c:1493
 evict+0x61e/0xb10 fs/inode.c:841
 free_local_statfs_inodes fs/gfs2/super.c:1532 [inline]
 gfs2_put_super+0x635/0x860 fs/gfs2/super.c:632
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9dcfb9da57
RSP: 002b:00007ffc75738058 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f9dcfc32048 RCX: 00007f9dcfb9da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc75738110
RBP: 00007ffc75738110 R08: 00007ffc75739110 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc757391a0
R13: 00007f9dcfc32048 R14: 0000000000068343 R15: 00007ffc757391e0
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:0H/11:
 #0: ffff888032252d40 ((wq_completion)gfs2-glock/syz:syz){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff888032252d40 ((wq_completion)gfs2-glock/syz:syz){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90000107c40 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90000107c40 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
1 lock held by khungtaskd/30:
 #0: ffffffff8e95d260 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e95d260 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e95d260 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5595:
 #0: ffff88803707a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5838:
 #0: ffff8880519f60d8 (&type->s_umount_key#114){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880519f60d8 (&type->s_umount_key#114){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff8880519f60d8 (&type->s_umount_key#114){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
1 lock held by syz-executor/5846:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd3/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: ac 78 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 21 1a 00 fb f4 <e9> 3c f0 02 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000242
RAX: 000000000127fa8f RBX: ffffffff819b142a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfc0ce0 RDI: ffffffff8c287de0
RBP: ffffc90000197f10 R08: ffff8880b87339db R09: 1ffff110170e673b
R10: dffffc0000000000 R11: ffffed10170e673c R12: 0000000000000001
R13: 1ffff11003bd0000 R14: 0000000000000001 R15: 1ffff11003bd0000
FS:  0000000000000000(0000) GS:ffff88812535c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000011000 CR3: 00000000759f6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>
----------------
Code disassembly (best guess):
   0:	ac                   	lods   %ds:(%rsi),%al
   1:	78 02                	js     0x5
   3:	c3                   	ret
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	cc                   	int3
   9:	cc                   	int3
   a:	cc                   	int3
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d 83 21 1a 00 	verw   0x1a2183(%rip)        # 0x1a21ab
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	e9 3c f0 02 00       	jmp    0x2f06b <-- trapping instruction
  2f:	cc                   	int3
  30:	cc                   	int3
  31:	cc                   	int3
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	cc                   	int3
  38:	cc                   	int3
  39:	cc                   	int3
  3a:	cc                   	int3
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/04 00:55 linux-next cc13002a9f98 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
2026/03/30 09:57 linux-next 3b058d1aeeef 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
2026/03/28 01:23 linux-next e77a5a5cfe43 74a13a23 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
2026/03/22 06:58 linux-next 785f0eb2f85d 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
2026/03/21 13:12 linux-next 785f0eb2f85d 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
2026/03/18 11:29 linux-next 8e5a478b6d6a 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
2026/03/14 00:01 linux-next b84a0ebe421c 351cb5cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task kworker/NUM:0H:NUM blocked in I/O wait for more than NUM seconds.
* Struck through repros no longer work on HEAD.