INFO: task syz.1.243:6778 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.243       state:D stack:28056 pid:6778  tgid:6777  ppid:5793   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x14de/0x5210 kernel/sched/core.c:6907
 __schedule_loop kernel/sched/core.c:6989 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285
 rt_mutex_slowlock_block+0x508/0x680 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+0x2dc/0x710 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+0x168/0x1d0 kernel/locking/rtmutex_api.c:552
 bdev_open+0xe0/0xcc0 block/bdev.c:961
 blkdev_open+0x485/0x620 block/fops.c:698
 do_dentry_open+0x83d/0x13e0 fs/open.c:949
 vfs_open+0x3b/0x350 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e3d/0x38a0 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f928ad6c84e
RSP: 002b:00007f9289005b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f92890066c0 RCX: 00007f928ad6c84e
RDX: 0000000000000080 RSI: 00007f9289005c00 RDI: ffffffffffffff9c
RBP: 00007f9289005c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f928b026038 R14: 00007f928b025fa0 R15: 00007ffea5aed708
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8dbcd480 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8dbcd480 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8dbcd480 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5549:
 #0: ffff8880323fd0a0 (&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+0x462/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by udevd/5808:
 #0: ffff888025fa54c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:961
3 locks held by kworker/1:5/5910:
2 locks held by kworker/u8:15/5996:
1 lock held by syz.1.243/6778:
 #0: ffff888025fa54c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:961
3 locks held by syz.2.558/7965:
4 locks held by syz.5.588/8029:
2 locks held by syz.0.583/8043:
3 locks held by syz.0.594/8055:
1 lock held by syz.3.599/8074:
1 lock held by syz.0.600/8076:
 #0: ffff888028130cd8 (sk_lock-AF_TIPC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline]
 #0: ffff888028130cd8 (sk_lock-AF_TIPC){+.+.}-{0:0}, at: tipc_wait_for_rcvmsg+0x345/0x640 net/tipc/socket.c:1848
4 locks held by syz.0.600/8077:

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

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 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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+0xf90/0xfe0 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 14 4c 02 e9 53 c2 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 32 17 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8d807dc0 EFLAGS: 00000246
RAX: 00000000005805b7 RBX: ffffffff819849cd RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d34722c RDI: ffffffff8b861580
RBP: ffffffff8d807eb0 R08: ffff8880b8833cdb R09: 1ffff1101710679b
R10: dffffc0000000000 R11: ffffed101710679c R12: ffffffff8f492870
R13: 1ffffffff1b205d8 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888126595000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 0000000040328000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1bd/0x500 kernel/sched/idle.c:332
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430
 rest_init+0x2de/0x300 init/main.c:757
 start_kernel+0x380/0x3d0 init/main.c:1206
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>