syzbot

INFO: task syz-executor:5951 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:20648 pid:5951  tgid:5951  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 bit_wait+0x11/0xd0 kernel/sched/wait_bit.c:240
 __wait_on_bit+0xb9/0x310 kernel/sched/wait_bit.c:52
 out_of_line_wait_on_bit+0x123/0x170 kernel/sched/wait_bit.c:67
 wait_on_bit include/linux/wait_bit.h:77 [inline]
 gfs2_glock_wait+0xbd/0x2a0 fs/gfs2/glock.c:1335
 gfs2_glock_nq_init fs/gfs2/glock.h:252 [inline]
 __gfs2_lookup+0x117/0x270 fs/gfs2/inode.c:984
 __lookup_slow+0x297/0x3d0 fs/namei.c:1816
 lookup_slow+0x53/0x70 fs/namei.c:1833
 walk_component+0x2d2/0x400 fs/namei.c:2151
 lookup_last fs/namei.c:2652 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2676
 filename_lookup+0x212/0x570 fs/namei.c:2705
 user_path_at+0x3a/0x60 fs/namei.c:3215
 ksys_umount fs/namespace.c:2061 [inline]
 __do_sys_umount fs/namespace.c:2069 [inline]
 __se_sys_umount fs/namespace.c:2067 [inline]
 __x64_sys_umount+0xee/0x160 fs/namespace.c:2067
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1896b902f7
RSP: 002b:00007fffd8149c88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f1896c11d7d RCX: 00007f1896b902f7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffd8149d40
RBP: 00007fffd8149d40 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffd814ae30
R13: 00007f1896c11d7d R14: 000055556c71c4a8 R15: 00007fffd814cff0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5579:
 #0: ffff88814da250a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5951:
 #0: ffff88805ade07e8 (&type->i_mutex_dir_key#8){.+.+}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
 #0: ffff88805ade07e8 (&type->i_mutex_dir_key#8){.+.+}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1832
3 locks held by syz.1.173/6656:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf60/0xfa0 kernel/hung_task.c:495
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6656 Comm: syz.1.173 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:srso_alias_safe_ret+0x5/0x7 arch/x86/lib/retpoline.S:213
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 48 8d 64 24 08 <c3> cc e8 f4 ff ff ff 0f 0b cc cc cc cc cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc9000b6b64b8 EFLAGS: 00000293
RAX: ffffffff8b489a01 RBX: 0000000000000000 RCX: ffff888031155ac0
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc9000b6b65e0 R08: ffffc9000b6b6557 R09: ffffc9000b6b6540
R10: dffffc0000000000 R11: fffff520016d6cab R12: ffffc9000b6b68c1
R13: 0000000000000003 R14: ffffc9000b6b68c1 R15: 0000000000000001
FS:  000055555e15f500(0000) GS:ffff888125d0b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5d9b7ff000 CR3: 0000000063faf000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 number+0x501/0xf60 lib/vsprintf.c:530
 vsnprintf+0x91b/0xf00 lib/vsprintf.c:2890
 sprintf+0xd9/0x120 lib/vsprintf.c:3089
 print_time kernel/printk/printk.c:1354 [inline]
 info_print_prefix+0x155/0x310 kernel/printk/printk.c:1380
 record_print_text+0x154/0x420 kernel/printk/printk.c:1429
 printk_get_next_message+0x26d/0x7b0 kernel/printk/printk.c:2997
 console_emit_next_record kernel/printk/printk.c:3065 [inline]
 console_flush_all+0x4ca/0xb10 kernel/printk/printk.c:3199
 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
 console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
 _printk+0xcf/0x120 kernel/printk/printk.c:2448
 set_capacity_and_notify+0x208/0x2d0 block/genhd.c:93
 loop_set_size+0x44/0xb0 drivers/block/loop.c:220
 loop_configure+0x9f8/0xe50 drivers/block/loop.c:1081
 lo_ioctl+0x806/0x1c50 drivers/block/loop.c:-1
 blkdev_ioctl+0x5af/0x6d0 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5da378ebcb
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007ffddf3cde70 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f5da378ebcb
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000012759
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffddf3cdfa0 R14: 00007ffddf3cdf60 R15: 00007f5d9a800000
 </TASK>