INFO: task kworker/u8:9:6480 blocked for more than 142 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:9 state:D stack:20392 pid:6480 tgid:6480 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-7:4) Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1539/0x5080 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138 write_inode fs/fs-writeback.c:1582 [inline] __writeback_single_inode+0x75a/0x1060 fs/fs-writeback.c:1813 writeback_sb_inodes+0x92e/0x1940 fs/fs-writeback.c:2041 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118 wb_writeback+0x459/0xad0 fs/fs-writeback.c:2229 wb_check_old_data_flush fs/fs-writeback.c:2333 [inline] wb_do_writeback fs/fs-writeback.c:2386 [inline] wb_workfn+0xaee/0xef0 fs/fs-writeback.c:2414 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e760160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e760160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e760160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:4/55: 2 locks held by udevd/5193: 2 locks held by getty/5577: #0: ffff8880375b80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 4 locks held by udevd/6012: 4 locks held by kworker/u8:9/6480: #0: ffff88801befd148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc9001a467c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 #2: ffff88803614e0e0 (&type->s_umount_key#90){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff88807e7acb08 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 4 locks held by syz.4.965/10929: 1 lock held by syz.7.1299/12912: #0: ffff88807b64c080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:601 1 lock held by syz.7.1299/12913: #0: ffff8880b843abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb6/0x150 kernel/sched/core.c:655 1 lock held by rm/12911: #0: ffff8880b843abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb6/0x150 kernel/sched/core.c:655 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 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:161 [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:347 [inline] watchdog+0xff4/0x1040 kernel/hung_task.c:516 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5908 Comm: kworker/0:4 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: events free_obj_work RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline] RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline] RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline] RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline] RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline] RIP: 0010:__lock_acquire+0x197b/0x2cf0 kernel/locking/lockdep.c:5237 Code: 14 25 ff 0f 00 00 39 05 9f 4a 7f 12 73 06 89 05 97 4a 7f 12 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 30 e3 62 RSP: 0018:ffffc90004e96e98 EFLAGS: 00000002 RAX: ffffffff96b77c58 RBX: 0000000000000111 RCX: 0000000000000002 RDX: ffffffff96a40bc8 RSI: ffff88807a2ac838 RDI: 0000000000000111 RBP: a4567d4052f1ec19 R08: ffffc90004e96e60 R09: 0000000000000020 R10: dffffc0000000000 R11: ffffffff81a17f00 R12: ffffc90004e96f28 R13: ffffffff93c1a7d0 R14: ffff88807a2abc80 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125296000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa4045e1198 CR3: 0000000052462000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162 lock_hrtimer_base kernel/time/hrtimer.c:172 [inline] hrtimer_try_to_cancel+0x22b/0x5b0 kernel/time/hrtimer.c:1363 update_curr_dl_se+0x2fe/0xeb0 kernel/sched/deadline.c:1485 update_curr+0x22b/0x4f0 kernel/sched/fair.c:1263 pick_task_fair+0xb7/0x2a0 kernel/sched/fair.c:8888 pick_task kernel/sched/core.c:5994 [inline] pick_next_task kernel/sched/core.c:6131 [inline] __schedule+0x3383/0x5080 kernel/sched/core.c:6848 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x17e/0x23c0 arch/x86/kernel/unwind_orc.c:-1 Code: f6 03 03 0f 85 e5 18 00 00 49 8d 5e 35 48 89 d8 48 c1 e8 03 48 89 44 24 28 0f b6 04 28 84 c0 0f 85 45 1b 00 00 4c 89 6c 24 48 <4c> 89 64 24 20 4c 89 7c 24 50 48 89 5c 24 18 0f b6 1b 48 8b 44 24 RSP: 0018:ffffc90004e97578 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc90004e9767d RCX: 0000000080000001 RDX: 00000000777cf82a RSI: ffffffff8c276fe0 RDI: ffffffff8c276fa0 RBP: dffffc0000000000 R08: ffffffff81763295 R09: ffffffff8e760160 R10: ffffc90004e97698 R11: ffffffff81b02c90 R12: 1ffff920009d2ec9 R13: ffffc90004e97698 R14: ffffc90004e97648 R15: ffffffff81763295 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2667 [inline] slab_free mm/slub.c:6079 [inline] kmem_cache_free+0x180/0x610 mm/slub.c:6205 free_object_list lib/debugobjects.c:326 [inline] free_obj_work+0x391/0x4c0 lib/debugobjects.c:513 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 EXT4-fs (loop7): error count since last fsck: 1 EXT4-fs (loop7): initial error at time 1769964405: __ext4_iget:5405: inode 11: block 524312 EXT4-fs (loop7): last error at time 1769964405: __ext4_iget:5405: inode 11: block 524312 ---------------- Code disassembly (best guess): 0: 14 25 adc $0x25,%al 2: ff 0f decl (%rdi) 4: 00 00 add %al,(%rax) 6: 39 05 9f 4a 7f 12 cmp %eax,0x127f4a9f(%rip) # 0x127f4aab c: 73 06 jae 0x14 e: 89 05 97 4a 7f 12 mov %eax,0x127f4a97(%rip) # 0x127f4aab 14: 48 8b 02 mov (%rdx),%rax 17: 48 89 df mov %rbx,%rdi 1a: 4c 39 e8 cmp %r13,%rax 1d: 0f 84 2c fe ff ff je 0xfffffe4f 23: 4c 89 60 30 mov %r12,0x30(%rax) 27: 48 8b 00 mov (%rax),%rax * 2a: 4c 39 e8 cmp %r13,%rax <-- trapping instruction 2d: 75 f4 jne 0x23 2f: 48 89 df mov %rbx,%rdi 32: e9 18 fe ff ff jmp 0xfffffe4f 37: 48 89 fb mov %rdi,%rbx 3a: 48 rex.W 3b: c7 .byte 0xc7 3c: c7 (bad) 3d: 30 e3 xor %ah,%bl 3f: 62 .byte 0x62