syzbot

INFO: task syz.0.17:4361 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:24208 pid: 4361 ppid:  4303 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 wait_on_page_bit_common+0x815/0xe00 mm/filemap.c:1356
 wait_on_page_locked include/linux/pagemap.h:688 [inline]
 gfs2_jhead_process_page+0x24e/0xbc0 fs/gfs2/lops.c:476
 gfs2_find_jhead+0xec2/0x1000 fs/gfs2/lops.c:597
 gfs2_make_fs_rw+0x1f4/0x560 fs/gfs2/super.c:140
 gfs2_fill_super+0x188a/0x1f50 fs/gfs2/ops_fstype.c:1276
 get_tree_bdev+0x3f1/0x610 fs/super.c:1325
 gfs2_get_tree+0x4d/0x1e0 fs/gfs2/ops_fstype.c:1332
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f53b0c53eea
RSP: 002b:00007fff29760498 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff29760520 RCX: 00007f53b0c53eea
RDX: 0000200000000140 RSI: 0000200000037f80 RDI: 00007fff297604e0
RBP: 0000200000000140 R08: 00007fff29760520 R09: 0000000002810000
R10: 0000000002810000 R11: 0000000000000246 R12: 0000200000037f80
R13: 00007fff297604e0 R14: 0000000000037fd1 R15: 00002000000001c0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: 
ffffffff8c11c720
 (
rcu_read_lock
){....}-{1:2}
, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3945:
 #0: 
ffff88802bb8c098
 (
&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
1 lock held by syz.0.17/4361:
 #0: ffff88807c2d20e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz-executor/4371:
 #0: ffff88801f7a9918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by udevd/4373:
 #0: ffff88801f7a9918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff88801f958468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 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+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1166 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue:  0x0 (phy7)
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:132 [inline]
RIP: 0010:lock_acquire+0x1ca/0x3f0 kernel/locking/lockdep.c:5626
Code: 0b 8a e8 d9 fc 45 08 b8 ff ff ff ff 65 0f c1 05 9c 7d a6 7e 83 f8 01 0f 85 fa 00 00 00 48 c7 84 24 80 00 00 00 00 00 00 00 9c <8f> 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41
RSP: 0018:ffffc90004a27a38 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 9eb93076a52fbb00
RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800
RBP: ffffc90004a27b50 R08: dffffc0000000000 R09: fffffbfff1ff5419
R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: ffff8880b913a358
R13: 1ffff92000944f54 R14: 0000000000000046 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe4614a1000 CR3: 0000000023e28000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 _raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:368
 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
 rq_lock kernel/sched/sched.h:1621 [inline]
 __schedule+0x2b7/0x4390 kernel/sched/core.c:6309
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 worker_thread+0xf5c/0x12a0 kernel/workqueue.c:2478
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>