INFO: task syz.0.2174:14470 blocked for more than 143 seconds. Not tainted 6.14.0-rc4-syzkaller-00242-g7a5668899f54 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.2174 state:D stack:24160 pid:14470 tgid:14470 ppid:12573 task_flags:0x400040 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 request_wait_answer fs/fuse/dev.c:453 [inline] __fuse_request_send fs/fuse/dev.c:467 [inline] __fuse_simple_request+0xe2a/0x1850 fs/fuse/dev.c:561 fuse_simple_request fs/fuse/fuse_i.h:1197 [inline] fuse_flush+0x6c0/0x990 fs/fuse/file.c:557 filp_flush+0xb9/0x190 fs/open.c:1540 filp_close+0x1e/0x40 fs/open.c:1553 __range_close fs/file.c:746 [inline] __do_sys_close_range fs/file.c:805 [inline] __se_sys_close_range+0x38b/0x6d0 fs/file.c:769 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: 0033:0x7f598af8d169 RSP: 002b:00007ffe15e69a88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: ffffffffffffffda RBX: 00007f598b1a7ba0 RCX: 00007f598af8d169 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f598b1a7ba0 R08: 0000000000022f18 R09: 0000001e15e69d7f R10: 00007f598b1a7ac0 R11: 0000000000000246 R12: 0000000000121313 R13: 00007f598b1a6080 R14: ffffffffffffffff R15: 00007ffe15e69ba0 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8eb38fa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8eb38fa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8eb38fa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746 2 locks held by getty/5589: #0: ffff888031a850a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x616/0x1770 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/12768: #0: ffff8880713ca0e0 (&type->s_umount_key#119){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880713ca0e0 (&type->s_umount_key#119){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8880713ca0e0 (&type->s_umount_key#119){++++}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505 4 locks held by kworker/u8:16/15568: 3 locks held by syz.5.2646/16140: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc4-syzkaller-00242-g7a5668899f54 #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+0x7ab/0x920 kernel/kthread.c:464 ret_from_fork+0x4d/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: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16140 Comm: syz.5.2646 Not tainted 6.14.0-rc4-syzkaller-00242-g7a5668899f54 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:io_serial_in+0x76/0xb0 drivers/tty/serial/8250/8250_port.c:409 Code: 90 d5 3d fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 b1 0f a5 fc 44 03 33 44 89 f2 ec <0f> b6 c0 5b 41 5e 41 5f 5d e9 47 57 8c fb 89 e9 80 e1 07 38 c1 7c RSP: 0018:ffffc9000c6ae878 EFLAGS: 00000002 RAX: 1ffffffff3532c00 RBX: ffffffff9a9960a0 RCX: 0000000000000000 RDX: 00000000000003fd RSI: 000000000007ffff RDI: 0000000000080000 RBP: 0000000000000000 R08: ffffffff8583e986 R09: 1ffff110049ef046 R10: dffffc0000000000 R11: ffffffff8583e940 R12: 0000000000000020 R13: 1ffffffff3532c66 R14: 00000000000003fd R15: dffffc0000000000 FS: 00007fc9028426c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc8f81ff000 CR3: 0000000064bb8000 CR4: 0000000000350ef0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr+0x1b3/0x320 drivers/tty/serial/8250/8250_port.c:2100 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3357 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3380 [inline] serial8250_console_write+0x134c/0x1e00 drivers/tty/serial/8250/8250_port.c:3465 console_emit_next_record kernel/printk/printk.c:3122 [inline] console_flush_all+0x86b/0xeb0 kernel/printk/printk.c:3210 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline] console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3309 vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2432 _printk+0xd5/0x120 kernel/printk/printk.c:2457 set_capacity_and_notify+0x211/0x2d0 block/genhd.c:93 loop_set_size+0x44/0xb0 drivers/block/loop.c:234 loop_configure+0xa82/0xf20 drivers/block/loop.c:1106 lo_ioctl+0x898/0x2870 blkdev_ioctl+0x5d2/0x6f0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892 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: 0033:0x7fc90198cd6b 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:00007fc902841dc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fc90198cd6b RDX: 0000000000000004 RSI: 0000000000004c00 RDI: 0000000000000005 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000004439 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 R13: 00007fc902841ef0 R14: 00007fc902841eb0 R15: 00007fc8f7200000