syzbot

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:21160 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: 0033:0x7fc5d359da57
RSP: 002b:00007ffc2a8982d8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007fc5d359da57
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffc2a899480
RBP: 00007fc5d3632048 R08: 00000000000105a0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc2a899480
R13: 00007fc5d3632048 R14: 0000555594ab64e8 R15: 00007ffc2a89a550
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8d1320a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d1320a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d1320a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by getty/5522:
 #0: ffff88814c5c10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000326e2f0 (&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: ffff8880318000e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880318000e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880318000e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz.2.756/9274:
2 locks held by sed/9294:

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

NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 17 Comm: rcu_preempt Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__free_object+0x141/0xa70 lib/debugobjects.c:352
Code: 42 80 3c 28 00 74 08 48 89 df e8 1a 0a ae fd 48 8b 1b 4c 8d a3 e8 8c 03 00 4c 89 e0 48 c1 e8 03 48 89 44 24 20 42 0f b6 04 28 <84> c0 0f 85 e8 08 00 00 48 8d 9b e0 8c 03 00 41 83 3c 24 40 48 89
RSP: 0018:ffffc90000167940 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff8880b8e00000 RCX: 2982f9f661868b00
RDX: 0000000000000000 RSI: ffffffff8b1c8980 RDI: ffffffff8b1c8940
RBP: ffffc90000167b18 R08: ffffffff8e8b02af R09: 1ffffffff1d16055
R10: dffffc0000000000 R11: fffffbfff1d16056 R12: ffff8880b8e38ce8
R13: dffffc0000000000 R14: dead000000000122 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556a61272950 CR3: 000000000cf32000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 free_object lib/debugobjects.c:424 [inline]
 debug_object_free+0x2c8/0x480 lib/debugobjects.c:867
 destroy_timer_on_stack kernel/time/timer.c:812 [inline]
 schedule_timeout+0x1a1/0x2d0 kernel/time/timer.c:2172
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 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>