INFO: task kworker/u8:4:67 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:4 state:D stack:25224 pid:67 tgid:67 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-7:1) Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked+0x1f84/0x25b0 kernel/locking/rtmutex.c:1787 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251 f2fs_down_write fs/f2fs/f2fs.h:2411 [inline] f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:180 f2fs_issue_checkpoint+0x414/0x6f0 fs/f2fs/checkpoint.c:2095 f2fs_balance_fs_bg+0x571/0x9d0 fs/f2fs/segment.c:545 f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2257 do_writepages+0x338/0x560 mm/page-writeback.c:2571 __writeback_single_inode+0x12e/0xf90 fs/fs-writeback.c:1787 writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2079 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2155 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2266 wb_check_old_data_flush fs/fs-writeback.c:2370 [inline] wb_do_writeback fs/fs-writeback.c:2449 [inline] wb_workfn+0xc98/0x10f0 fs/fs-writeback.c:2477 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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:162 [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:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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: 10727 Comm: syz.8.543 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:417 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 9b b0 0d f6 cc RSP: 0018:ffffc90006327508 EFLAGS: 00000297 RAX: ffffffff8b1f5e83 RBX: ffffc90006327638 RCX: ffff88805d938000 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000003 R12: ffffc90006327620 R13: 00000000000001d6 R14: ffffc90006327628 R15: 1ffff92000c64ec7 FS: 00007f6d5744e6c0(0000) GS:ffff888126244000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005611a97a8ee8 CR3: 000000003c182000 CR4: 00000000003526f0 Call Trace: xas_find+0x193/0x980 lib/xarray.c:1409 find_get_entry mm/filemap.c:2080 [inline] find_lock_entries+0x208/0xad0 mm/filemap.c:2184 shmem_undo_range+0x2c7/0x15d0 mm/shmem.c:1131 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x280/0xa80 mm/shmem.c:1407 evict+0x624/0xb50 fs/inode.c:828 dentry_kill+0x1b9/0x880 fs/dcache.c:826 finish_dput+0x1a/0x260 fs/dcache.c:1001 __fput+0x699/0xa80 fs/file_table.c:520 fput_close_sync+0x11f/0x240 fs/file_table.c:617 __do_sys_close fs/open.c:1538 [inline] __se_sys_close fs/open.c:1523 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1523 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6d591bd68e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007f6d5744dda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007f6d5744e6c0 RCX: 00007f6d591bd68e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008 RBP: 0000000000000010 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008 R13: 00007f6d5744dee0 R14: 00007f6d5744dea0 R15: 00007f6d4f00d000