syzbot

INFO: task syz-executor:5930 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:21112 pid:5930  tgid:5930  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1480/0x50a0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241
 rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
 rt_mutex_slowlock+0x2a8/0x6b0 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
 mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:552
 lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
 jfs_umount+0x2ef/0x3c0 fs/jfs/jfs_umount.c:114
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1722
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f49a6f60a77
RSP: 002b:00007fffe6a9d208 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f49a6fe3d7d RCX: 00007f49a6f60a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffe6a9d2c0
RBP: 00007fffe6a9d2c0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffe6a9e350
R13: 00007f49a6fe3d7d R14: 0000000000024a86 R15: 00007fffe6a9e390
 </TASK>
INFO: task syz-executor:5932 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:21464 pid:5932  tgid:5932  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1480/0x50a0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241
 rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
 rt_mutex_slowlock+0x2a8/0x6b0 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
 mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:552
 lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
 jfs_umount+0x2ef/0x3c0 fs/jfs/jfs_umount.c:114
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1722
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe74ee40a77
RSP: 002b:00007ffc720f0948 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fe74eec3d7d RCX: 00007fe74ee40a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc720f0a00
RBP: 00007ffc720f0a00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc720f1a90
R13: 00007fe74eec3d7d R14: 0000000000024de3 R15: 00007ffc720f1ad0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8d5ae880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8d5ae880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8d5ae880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5558:
 #0: ffff8880268fb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5921:
 #0: ffff888036aee0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888036aee0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888036aee0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/5930:
 #0: ffff8880277f00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff8880277f00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff8880277f00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/5932:
 #0: ffff88803827e0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff88803827e0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff88803827e0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
4 locks held by kworker/0:7/6069:
2 locks held by syz-executor/6073:
 #0: ffff888034aa80d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888034aa80d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888034aa80d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/6101:
 #0: ffff8880597c60d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff8880597c60d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff8880597c60d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/6102:
 #0: ffff888032e840d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888032e840d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888032e840d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/6105:
 #0: ffff8880578e40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff8880578e40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff8880578e40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/6121:
 #0: ffff888029aa40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888029aa40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888029aa40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/6218:
 #0: ffff888142ed00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888142ed00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888142ed00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8d9f98b8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
1 lock held by syz-executor/6282:
 #0: ffff88803c57c0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff88803c57c0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff88803c57c0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
1 lock held by syz.6.412/6809:
3 locks held by syz.4.413/6810:
2 locks held by syz.0.414/6811:
3 locks held by syz.3.415/6812:
3 locks held by syz.5.416/6813:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xf95/0xfe0 kernel/hung_task.c:515
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6069 Comm: kworker/0:7 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:rtlock_lock kernel/locking/spinlock_rt.c:40 [inline]
RIP: 0010:__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
RIP: 0010:rt_spin_lock+0xeb/0x3e0 kernel/locking/spinlock_rt.c:57
Code: 00 e8 d9 c8 bc f6 48 c7 c0 70 1c db 8e 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 58 02 00 00 4c 8d 7c 24 40 83 3d d5 97 05 04 00 <74> 28 4c 8d a3 10 0b 00 00 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74
RSP: 0018:ffffc90003f07920 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff888023edbc80 RCX: 2e50167159896c00
RDX: ffff888023edbc80 RSI: ffffffff8cfdf958 RDI: ffffffff8b3f4de0
RBP: ffffc90003f079d8 R08: ffffffff85bd13ed R09: ffffffff8dff6df8
R10: dffffc0000000000 R11: fffffbfff1db618f R12: ffff88803f592dd0
R13: dffffc0000000000 R14: ffffffff8dff6da0 R15: ffffc90003f07960
FS:  0000000000000000(0000) GS:ffff888126d06000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f937eece000 CR3: 00000000351b8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 spin_lock include/linux/spinlock_rt.h:44 [inline]
 wg_ratelimiter_gc_entries+0x5d/0x480 drivers/net/wireguard/ratelimiter.c:63
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>