INFO: task syz.7.6027:25132 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.7.6027 state:D stack:23720 pid:25132 tgid:25130 ppid:17565 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776 sync_bdevs+0x27e/0x470 block/bdev.c:1305 ksys_sync+0xb9/0x150 fs/sync.c:105 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f664498f749 RSP: 002b:00007f66457ea038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f6644be5fa0 RCX: 00007f664498f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f6644be5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6644be6038 R14: 00007f6644be5fa0 R15: 00007ffd8100bc48 Showing all locks held in the system: 1 lock held by khungtaskd/32: #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:12/3571: #0: ffff88801bb86948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801bb86948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9000c7efbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000c7efbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 2 locks held by getty/5580: #0: ffff88814d1490a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 ( &ldata->atomic_read_lock ){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 1 lock held by udevd/5886: #0: ffff888025603358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 9 locks held by kworker/0:11/11594: 1 lock held by syz.7.6027/25132: #0: ffff888025603358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470 block/bdev.c:1305 1 lock held by syz.3.7192/28663: #0: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #0: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2b1/0x6e0 kernel/rcu/tree_exp.h:956 2 locks held by syz.8.7206/28682: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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: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+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 28661 Comm: syz.9.7197 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:407 Code: de a6 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 cc fe 0c fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 a2 29 f6 fb cc 44 89 f9 80 e1 07 38 c1 RSP: 0018:ffffc9000d456990 EFLAGS: 00000002 RAX: 000000000000002e RBX: 000000000000002e RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 0000000000001dd2 RDI: 0000000000001dd3 RBP: 00000000000003f8 R08: ffff888140590237 R09: 1ffff110280b2046 R10: dffffc0000000000 R11: ffffffff851a16e0 R12: dffffc0000000000 R13: ffffffff998f59e7 R14: ffffffff99c0a2a0 R15: 0000000000000000 FS: 00007f0bd4b726c0(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f815ff8 CR3: 000000008e9f8000 CR4: 0000000000350ef0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x13c5/0x1b60 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3129 [inline] console_flush_one_record kernel/printk/printk.c:3215 [inline] console_flush_all+0x713/0xb00 kernel/printk/printk.c:3289 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3359 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426 _printk+0xcf/0x120 kernel/printk/printk.c:2451 bio_check_eod block/blk-core.c:565 [inline] submit_bio_noacct+0x117a/0x1b60 block/blk-core.c:801 __submit_merged_bio+0x256/0x660 fs/f2fs/data.c:540 __f2fs_submit_merged_write fs/f2fs/data.c:635 [inline] __submit_merged_write_cond+0x269/0x530 fs/f2fs/data.c:657 f2fs_folio_wait_writeback+0x14c/0x240 fs/f2fs/segment.c:4243 f2fs_convert_inline_folio+0x6a9/0xd50 fs/f2fs/inline.c:198 f2fs_convert_inline_inode+0x7c4/0x880 fs/f2fs/inline.c:249 f2fs_punch_hole+0x24/0x390 fs/f2fs/file.c:1273 f2fs_fallocate+0x536/0x970 fs/f2fs/file.c:2029 vfs_fallocate+0x669/0x7e0 fs/open.c:339 madvise_remove mm/madvise.c:1046 [inline] madvise_vma_behavior+0x28bd/0x4170 mm/madvise.c:1360 madvise_walk_vmas+0x575/0xaf0 mm/madvise.c:1721 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1937 do_madvise+0x1bc/0x270 mm/madvise.c:2030 __do_sys_madvise mm/madvise.c:2039 [inline] __se_sys_madvise mm/madvise.c:2037 [inline] __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:2037 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0bd3d8f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0bd4b72038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f0bd3fe5fa0 RCX: 00007f0bd3d8f749 RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000200000000000 RBP: 00007f0bd3e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0bd3fe6038 R14: 00007f0bd3fe5fa0 R15: 00007ffcfc7727f8