INFO: task kworker/u8:22:4053 blocked for more than 143 seconds. Tainted: G W syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:22 state:D stack:20328 pid:4053 tgid:4053 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 f2fs_down_write fs/f2fs/f2fs.h:2234 [inline] f2fs_balance_fs+0x5af/0x7f0 fs/f2fs/segment.c:464 f2fs_write_inode+0x3fb/0x5f0 fs/f2fs/inode.c:820 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x6f4/0x1000 fs/fs-writeback.c:1745 writeback_sb_inodes+0x6b7/0xf60 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xaf4/0xf00 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: lockdep is turned off. NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: 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] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6738 Comm: syz.0.108 Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:unwind_next_frame+0xc9c/0x2390 arch/x86/kernel/unwind_orc.c:-1 Code: 4c 8b 6c 24 50 4c 8b 64 24 10 74 08 48 89 df e8 ba d2 aa 00 4c 89 23 ba 10 00 00 00 4c 89 ef 31 f6 e8 88 d4 aa 00 48 8b 14 24 c5 04 00 00 4c 89 7c 24 28 48 89 5c 24 78 4d 8d 66 08 4d 89 e5 RSP: 0018:ffffc90003f96438 EFLAGS: 00000246 RAX: ffffc90003f96558 RBX: ffffc90003f96540 RCX: 0000000000000000 RDX: ffffffff8fd25444 RSI: 0000000000000000 RDI: ffffc90003f96568 RBP: dffffc0000000000 R08: ffffc90003f96567 R09: 0000000000000000 R10: ffffc90003f96558 R11: fffff520007f2cad R12: ffffc90003f97980 R13: ffffc90003f96558 R14: ffffc90003f96508 R15: ffffc90003f96550 FS: 00007f78fcba66c0(0000) GS:ffff8881269c5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f83a3becfeb CR3: 000000003dbb6000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 slab_free_hook mm/slub.c:2378 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x3ef/0x510 mm/slub.c:4782 f2fs_read_end_io+0x398/0x9d0 fs/f2fs/data.c:-1 f2fs_submit_page_read+0x116/0x190 fs/f2fs/data.c:1110 f2fs_get_read_data_folio+0x4a4/0x7d0 fs/f2fs/data.c:1268 gc_data_segment fs/f2fs/gc.c:1641 [inline] do_garbage_collect+0x3898/0x6410 fs/f2fs/gc.c:1826 f2fs_gc+0xca9/0x2580 fs/f2fs/gc.c:1931 f2fs_balance_fs+0x5fb/0x7f0 fs/f2fs/segment.c:466 f2fs_map_blocks+0x2847/0x4130 fs/f2fs/data.c:1746 f2fs_expand_inode_data+0x5b1/0xa60 fs/f2fs/file.c:1923 f2fs_fallocate+0x4f8/0x990 fs/f2fs/file.c:2026 vfs_fallocate+0x66f/0x7f0 fs/open.c:342 ioctl_preallocate fs/ioctl.c:290 [inline] file_ioctl+0x61d/0x780 fs/ioctl.c:-1 do_vfs_ioctl+0xb36/0x1440 fs/ioctl.c:577 __do_sys_ioctl fs/ioctl.c:596 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f78fe93ebe9 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:00007f78fcba6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f78feb65fa0 RCX: 00007f78fe93ebe9 RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000007 RBP: 00007f78fe9c1e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f78feb66038 R14: 00007f78feb65fa0 R15: 00007fff99af91c8