syzbot

INFO: task syz.0.18:4451 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.18        state:D stack:25168 pid:4451  ppid:4381   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168
 gfs2_gl_hash_clear+0x1a2/0x2f0 fs/gfs2/glock.c:2263
 gfs2_fill_super+0x1699/0x1f80 fs/gfs2/ops_fstype.c:1304
 get_tree_bdev+0x3f1/0x610 fs/super.c:1366
 gfs2_get_tree+0x4d/0x1e0 fs/gfs2/ops_fstype.c:1327
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3606
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8c8b390eea
RSP: 002b:00007ffc1d0135e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc1d013670 RCX: 00007f8c8b390eea
RDX: 000020000001f680 RSI: 000020000001f6c0 RDI: 00007ffc1d013630
RBP: 000020000001f680 R08: 00007ffc1d013670 R09: 0000000000000084
R10: 0000000000000084 R11: 0000000000000246 R12: 000020000001f6c0
R13: 00007ffc1d013630 R14: 000000000001f7c6 R15: 0000200000000540
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92bab0
 (
rcu_tasks.tasks_gp_mutex
){+.+.}-{3:3}
, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: 
ffffffff8c92c2d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4029:
 #0: ffff88802fbdf098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by syz.0.18/4451:
 #0: ffff8880283be0e0 (&type->s_umount_key#52/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x930 fs/super.c:228

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 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+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 51 Comm: kworker/u4:3 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:check_wait_context kernel/locking/lockdep.c:4739 [inline]
RIP: 0010:__lock_acquire+0x70d/0x7c50 kernel/locking/lockdep.c:4999
Code: 83 f8 31 73 43 48 8d 04 9b 49 8d 5c c5 00 48 89 d8 48 c1 e8 03 42 0f b6 04 00 84 c0 75 45 8b 1b 48 8b 44 24 50 42 0f b6 04 00 <84> c0 75 55 48 8b 44 24 18 33 18 41 ff ce 49 ff cf f7 c3 00 60 00
RSP: 0000:ffffc90000bc7780 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 00000000000406b5 RCX: ffff88801d6a3b80
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff908c8310
RBP: ffffc90000bc79d0 R08: dffffc0000000000 R09: fffffbfff2119063
R10: fffffbfff2119063 R11: 1ffffffff2119062 R12: 0000000000000000
R13: ffff88801d6a4680 R14: 0000000000000002 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3ffa92000 CR3: 000000002f619000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:442
 batadv_nc_worker+0x365/0x600 net/batman-adv/network-coding.c:722
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>