syzbot

INFO: task kworker/0:5:4255 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:5     state:D stack:25360 pid: 4255 ppid:     2 flags:0x00004000
Workqueue: gfs_recovery gfs2_recover_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 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+0x83b/0xe50 mm/filemap.c:1356
 wait_on_page_locked include/linux/pagemap.h:688 [inline]
 gfs2_jhead_process_page+0x252/0xbf0 fs/gfs2/lops.c:476
 gfs2_find_jhead+0xec2/0x1000 fs/gfs2/lops.c:597
 gfs2_recover_func+0x73a/0x1cf0 fs/gfs2/recovery.c:462
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz.0.17:4482 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: 4482 ppid:  4364 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 bit_wait+0xd/0xc0 kernel/sched/wait_bit.c:199
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
 wait_on_bit include/linux/wait_bit.h:76 [inline]
 gfs2_recover_journal+0x104/0x150 fs/gfs2/recovery.c:579
 init_journal+0x1779/0x22f0 fs/gfs2/ops_fstype.c:837
 init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:891
 gfs2_fill_super+0x16b2/0x1f00 fs/gfs2/ops_fstype.c:1249
 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+0x2e3/0x3d0 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: 0033:0x7fa8456c3a8a
RSP: 002b:00007ffdc7da92d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdc7da9360 RCX: 00007fa8456c3a8a
RDX: 0000200000037f40 RSI: 0000200000037f80 RDI: 00007ffdc7da9320
RBP: 0000200000037f40 R08: 00007ffdc7da9360 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000037f80
R13: 00007ffdc7da9320 R14: 0000000000037f8e R15: 0000200000000040
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/1:0/21:
 #0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x499/0x7d0 kernel/sched/psi.c:882
1 lock held by khungtaskd/27:
 #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3945:
 #0: ffff88802babd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:5/4255:
 #0: ffff88801d36d138 ((wq_completion)gfs_recovery){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc90002e8fd00 ((work_completion)(&jd->jd_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
1 lock held by syz.0.17/4482:
 #0: ffff8880795f00e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by udevd/4565:
 #0: ffff88801f9be118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by syz.1.202/4774:
 #0: ffff88801f9be118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff888148334468 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:2071

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

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 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 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: 4774 Comm: syz.1.202 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:io_serial_in+0x73/0xb0 drivers/tty/serial/8250/8250_port.c:461
Code: e8 b2 81 29 fd 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 f3 8c 6e fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 44 89 f9 80 e1 07 38 c1 7c aa 4c
RSP: 0018:ffffc900039eef50 EFLAGS: 00000002
RAX: 1ffffffff2cc0360 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000020 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200073dde0 R12: dffffc0000000000
R13: 1ffffffff2c63b30 R14: ffffffff96601840 R15: 0000000000000000
FS:  000055556a034500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ec6f55000 CR3: 000000005cfa4000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:116 [inline]
 wait_for_xmitr+0x4c/0x260 drivers/tty/serial/8250/8250_port.c:2069
 serial8250_console_putchar+0x1a/0x50 drivers/tty/serial/8250/8250_port.c:3309
 uart_console_write+0xaa/0x100 drivers/tty/serial/serial_core.c:1981
 serial8250_console_write+0xc46/0x1000 drivers/tty/serial/8250/8250_port.c:3386
 call_console_drivers kernel/printk/printk.c:-1 [inline]
 console_unlock+0xb9a/0x1120 kernel/printk/printk.c:2744
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 __show_trace_log_lvl+0xdd/0x550 arch/x86/kernel/dumpstack.c:195
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 sysfs_warn_dup fs/sysfs/dir.c:30 [inline]
 sysfs_create_dir_ns+0x26a/0x290 fs/sysfs/dir.c:64
 create_dir lib/kobject.c:89 [inline]
 kobject_add_internal+0x6e0/0xd90 lib/kobject.c:263
 kobject_add_varg lib/kobject.c:398 [inline]
 kobject_init_and_add+0x128/0x190 lib/kobject.c:481
 gfs2_sys_fs_add+0x24f/0x4b0 fs/gfs2/sys.c:727
 gfs2_fill_super+0x120f/0x1f00 fs/gfs2/ops_fstype.c:1202
 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+0x2e3/0x3d0 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: 0033:0x7fd5880f0a8a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd59a6e928 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd59a6e9b0 RCX: 00007fd5880f0a8a
RDX: 0000200000037f40 RSI: 0000200000037f80 RDI: 00007ffd59a6e970
RBP: 0000200000037f40 R08: 00007ffd59a6e9b0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000037f80
R13: 00007ffd59a6e970 R14: 0000000000037f8e R15: 0000200000000040
 </TASK>