INFO: task kworker/u4:3:426 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:3 state:D stack:23616 pid: 426 ppid: 2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28 hfsplus_cat_write_inode+0x1e3/0x820 fs/hfsplus/inode.c:588 write_inode fs/fs-writeback.c:1495 [inline] __writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1705 writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2001 wb_writeback+0x455/0xb90 fs/fs-writeback.c:2106 wb_check_background_flush fs/fs-writeback.c:2172 [inline] wb_do_writeback fs/fs-writeback.c:2260 [inline] wb_workfn+0xb47/0xe60 fs/fs-writeback.c:2288 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 4 locks held by kworker/u4:3/426: #0: ffff8881419a8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90002f5fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88801a5ba0e0 (&type->s_umount_key#51){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88807d8fa0b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28 1 lock held by udevd/3561: 2 locks held by getty/3949: #0: ffff88802be16098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 9 locks held by syz-executor.0/4595: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4595 Comm: syz-executor.0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3681 [inline] RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3701 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3756 [inline] RIP: 0010:__lock_acquire+0x1430/0x7c60 kernel/locking/lockdep.c:5012 Code: 03 48 89 44 24 50 42 80 3c 00 00 74 12 48 89 df e8 e5 20 60 00 49 b8 00 00 00 00 00 fc ff df 48 89 9c 24 80 00 00 00 48 8b 1b <48> 85 db 0f 94 c0 48 83 c3 f8 0f 94 c1 08 c1 0f 84 83 02 00 00 e8 RSP: 0018:ffffc90000dd0800 EFLAGS: 00000046 RAX: 1ffffffff1fa9e72 RBX: ffffffff8ffef648 RCX: ffffffff815c110d RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbd0d0 RBP: ffffc90000dd0a50 R08: dffffc0000000000 R09: fffffbfff1ff7a1b R10: fffffbfff1ff7a1b R11: 1ffffffff1ff7a1a R12: 1f523f5682bb91d0 R13: ffff88801a3f1dc0 R14: 0000000082bb91d0 R15: ffff88801a3f29c0 FS: 00007fe42ed0f6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f747d193c00 CR3: 0000000079b0f000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 call_timer_fn+0xd7/0x530 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:console_trylock_spinning+0x2cd/0x350 kernel/printk/printk.c:1909 Code: 85 db 74 9d e8 64 a2 18 00 fb 31 c0 eb 48 e8 5a a2 18 00 e8 95 06 4a 08 48 85 db 74 d1 e8 4b a2 18 00 fb 48 c7 c7 a0 11 11 8c <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 68 06 28 5f RSP: 0018:ffffc90002d8f520 EFLAGS: 00000293 RAX: ffffffff815f2805 RBX: 0000000000000200 RCX: ffff88801a3f1dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c1111a0 RBP: ffffc90002d8f5f0 R08: dffffc0000000000 R09: fffffbfff1ff7a40 R10: fffffbfff1ff7a40 R11: 1ffffffff1ff7a3f R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff920005b1ea4 vprintk_emit+0xa7/0x150 kernel/printk/printk.c:2273 _printk+0xcc/0x110 kernel/printk/printk.c:2299 hfsplus_bnode_read_u16 fs/hfsplus/bnode.c:103 [inline] hfsplus_bnode_dump+0x30b/0x430 fs/hfsplus/bnode.c:410 hfsplus_brec_remove+0x476/0x540 fs/hfsplus/brec.c:229 __hfsplus_delete_attr+0x1d1/0x360 fs/hfsplus/attributes.c:299 hfsplus_delete_all_attrs+0x240/0x3a0 fs/hfsplus/attributes.c:378 hfsplus_delete_cat+0x94a/0xd20 fs/hfsplus/catalog.c:425 hfsplus_unlink+0x33c/0x760 fs/hfsplus/dir.c:385 vfs_unlink+0x385/0x600 fs/namei.c:4280 do_unlinkat+0x382/0x6f0 fs/namei.c:4348 __do_sys_unlink fs/namei.c:4396 [inline] __se_sys_unlink fs/namei.c:4394 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4394 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fe42f98db29 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe42ed0f0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 00007fe42faacf80 RCX: 00007fe42f98db29 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140 RBP: 00007fe42f9d947a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fe42faacf80 R15: 00007ffde483d4c8