INFO: task syz.3.2871:16779 blocked for more than 143 seconds. Not tainted 6.14.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.2871 state:D stack:26432 pid:16779 tgid:16778 ppid:15031 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914 __mutex_lock_common kernel/locking/mutex.c:662 [inline] __mutex_lock+0x817/0x1010 kernel/locking/mutex.c:730 sync_bdevs+0x1ae/0x340 block/bdev.c:1246 ksys_sync+0xe2/0x1c0 fs/sync.c:105 __do_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0cb7b8d169 RSP: 002b:00007f0cb89a0038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f0cb7da5fa0 RCX: 00007f0cb7b8d169 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f0cb7da5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f0cb7da5fa0 R15: 00007ffcb3b8cfa8 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746 2 locks held by getty/5586: #0: ffff8880325ee0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x616/0x1770 drivers/tty/n_tty.c:2211 1 lock held by udevd/9768: #0: ffff888025f5a4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xf0/0xc50 block/bdev.c:903 2 locks held by kworker/u8:0/10023: 3 locks held by kworker/u8:23/16327: 1 lock held by syz.3.2871/16779: #0: ffff888025f5a4c8 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ae/0x340 block/bdev.c:1246 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0x1058/0x10a0 kernel/hung_task.c:399 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: igorplugusb 8-1:0.0: receive overflow invalid: 63 NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111