Message-ID: <436f1a6997b0b257e538b079c3be766de34df98d.camel@ibm.com>
Date: Fri, 1 Aug 2025 17:48:07 +0000
From: Viacheslav Dubeyko <Slava.Dubeyko@....com>
To: "syzkaller-bugs@...glegroups.com" <syzkaller-bugs@...glegroups.com>,
        "frank.li@...o.com" <frank.li@...o.com>,
        "glaubitz@...sik.fu-berlin.de"
	<glaubitz@...sik.fu-berlin.de>,
        "linux-fsdevel@...r.kernel.org"
	<linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>,
        "syzbot+6f9eae7d87e0afb22029@...kaller.appspotmail.com"
	<syzbot+6f9eae7d87e0afb22029@...kaller.appspotmail.com>,
        "slava@...eyko.com"
	<slava@...eyko.com>
Subject: Re:  [syzbot] [hfs?] INFO: task hung in hfsplus_find_init (3)

On Fri, 2025-08-01 at 10:38 -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 

Issue has been created:
https://github.com/hfs-linux-kernel/hfs-linux-kernel/issues/237

Thanks,
Slava.

> HEAD commit:    f2d282e1dfb3 Merge tag 'bitmap-for-6.17' of https://github  ..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=144faf82580000  
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8b51b56c81c0761d  
> dashboard link: https://syzkaller.appspot.com/bug?extid=6f9eae7d87e0afb22029  
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=124faf82580000  
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=100642a2580000  
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/70f09e088d5c/disk-f2d282e1.raw.xz  
> vmlinux: https://storage.googleapis.com/syzbot-assets/9baa408863b9/vmlinux-f2d282e1.xz  
> kernel image: https://storage.googleapis.com/syzbot-assets/36063ac42323/bzImage-f2d282e1.xz  
> mounted in repro: https://storage.googleapis.com/syzbot-assets/7fea0d017f73/mount_0.gz  
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+6f9eae7d87e0afb22029@...kaller.appspotmail.com
> 
> INFO: task kworker/u8:3:49 blocked for more than 143 seconds.
>       Not tainted 6.16.0-syzkaller-10355-gf2d282e1dfb3 #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/u8:3    state:D
>  stack:21000 pid:49    tgid:49    ppid:2      task_flags:0x4208160 flags:0x00004000
> Workqueue: writeback wb_workfn
>  (flush-7:0)
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5357 [inline]
>  __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
>  __schedule_loop kernel/sched/core.c:7043 [inline]
>  schedule+0x165/0x360 kernel/sched/core.c:7058
>  schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
>  __mutex_lock_common kernel/locking/mutex.c:676 [inline]
>  __mutex_lock+0x7e3/0x1340 kernel/locking/mutex.c:760
>  hfsplus_find_init+0x15a/0x1d0 fs/hfsplus/bfind.c:28
>  hfsplus_cat_write_inode+0x1e6/0x7a0 fs/hfsplus/inode.c:592
>  write_inode fs/fs-writeback.c:1525 [inline]
>  __writeback_single_inode+0x6f1/0xff0 fs/fs-writeback.c:1745
>  writeback_sb_inodes+0x6c7/0x1010 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+0xaef/0xef0 fs/fs-writeback.c:2343
>  process_one_work kernel/workqueue.c:3236 [inline]
>  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
>  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
>  kthread+0x711/0x8a0 kernel/kthread.c:464
>  ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
> 
> Showing all locks held in the system:
> 1 lock held by khungtaskd/31:
>  #0: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
>  #0: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
>  #0: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
> 4 locks held by kworker/u8:3/49:
>  #0: ffff8881412ee948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
>  #0: ffff8881412ee948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
>  #1: ffffc90000b97bc0 (
> (work_completion)(&(&wb->dwork)->work)
> ){+.+.}-{0:0}
> , at: process_one_work kernel/workqueue.c:3212 [inline]
> , at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
>  #2: ffff8880332b00e0
>  (
> &type->s_umount_key
> #42
> ){.+.+}-{4:4}
> , at: super_trylock_shared+0x20/0xf0 fs/super.c:563
>  #3: 
> ffff8880792320b0
>  (
> &tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x15a/0x1d0 fs/hfsplus/bfind.c:28
> 5 locks held by kworker/u8:4/61:
>  #0: 
> ffff8880b8739f58
>  (
> &rq->__lock
> ){-.-.}-{2:2}
> , at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636
>  #1: 
> ffff8880b8724008
>  (
> per_cpu_ptr(&psi_seq, cpu)){-.-.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
> per_cpu_ptr(&psi_seq, cpu)){-.-.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
>  #2: ffffffff8dfd2f50 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_disable+0x12/0x20 kernel/jump_label.c:247
>  #3: ffffffff99c6aca8 (
> &obj_hash[i].lock
> ){-.-.}-{2:2}
> , at: debug_object_activate+0xbb/0x420 lib/debugobjects.c:818
>  #4: 
> ffffffff8dfe6308
>  (
> text_mutex
> ){+.+.}-{4:4}
> , at: arch_jump_label_transform_apply+0x17/0x30 arch/x86/kernel/jump_label.c:145
> 2 locks held by getty/5605:
>  #0: 
> ffff88803031a0a0
>  (
> &tty->ldisc_sem
> ){++++}-{0:0}
> , at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
>  #1: 
> ffffc900036c32f0
>  (
> &ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
> 4 locks held by syz-executor384/5873:
> 
> =============================================
> 
> NMI backtrace for cpu 0
> CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-syzkaller-10355-gf2d282e1dfb3 #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
> Call Trace:
>  <TASK>
>  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:307 [inline]
>  watchdog+0xf93/0xfe0 kernel/hung_task.c:470
>  kthread+0x711/0x8a0 kernel/kthread.c:464
>  ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
> Sending NMI from CPU 0 to CPUs 1:
> NMI backtrace for cpu 1
> CPU: 1 UID: 0 PID: 5873 Comm: syz-executor384 Not tainted 6.16.0-syzkaller-10355-gf2d282e1dfb3 #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
> RIP: 0010:kasan_check_range+0xd/0x2c0 mm/kasan/generic.c:188
> Code: 0f 0b 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 90 90 66 0f 1f 00 55 41 57 41 56 41 55 41 54 <53> b0 01 48 85 f6 0f 84 ba 01 00 00 4c 8d 04 37 49 39 f8 0f 82 82
> RSP: 0018:ffffc9000414eb30 EFLAGS: 00000056
> RAX: 00000000ffffff01 RBX: ffffffff99dbe400 RCX: ffffffff819df6c1
> RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc9000414eba0
> RBP: ffffc9000414ec10 R08: ffffffff99dbe403 R09: 1ffffffff33b7c80
> R10: dffffc0000000000 R11: fffffbfff33b7c81 R12: ffffffff99dbe410
> R13: ffffffff99dbe408 R14: 1ffffffff33b7c82 R15: 1ffffffff33b7c81
> FS:  0000555574d53380(0000) GS:ffff888125d5c000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffcbbc35f19 CR3: 00000000714b1000 CR4: 0000000000350ef0
> Call Trace:
>  <TASK>
>  instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
>  atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1301 [inline]
>  queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
>  do_raw_spin_lock+0x121/0x290 kernel/locking/spinlock_debug.c:116
>  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
>  _raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162
>  uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
>  serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3355
>  console_emit_next_record kernel/printk/printk.c:3138 [inline]
>  console_flush_all+0x728/0xc40 kernel/printk/printk.c:3226
>  __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
>  console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
>  vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
>  _printk+0xcf/0x120 kernel/printk/printk.c:2475
>  hfsplus_bnode_read_u16 fs/hfsplus/bnode.c:101 [inline]
>  hfsplus_bnode_dump+0x322/0x450 fs/hfsplus/bnode.c:403
>  hfsplus_brec_remove+0x480/0x550 fs/hfsplus/brec.c:229
>  __hfsplus_delete_attr+0x1d4/0x360 fs/hfsplus/attributes.c:299
>  hfsplus_delete_attr+0x231/0x2d0 fs/hfsplus/attributes.c:345
>  hfsplus_removexattr fs/hfsplus/xattr.c:796 [inline]
>  __hfsplus_setxattr+0x768/0x1fe0 fs/hfsplus/xattr.c:279
>  hfsplus_setxattr+0x11e/0x180 fs/hfsplus/xattr.c:436
>  hfsplus_user_setxattr+0x40/0x60 fs/hfsplus/xattr_user.c:30
>  __vfs_removexattr+0x431/0x470 fs/xattr.c:518
>  __vfs_removexattr_locked+0x1ed/0x230 fs/xattr.c:553
>  vfs_removexattr+0x80/0x1b0 fs/xattr.c:575
>  removexattr fs/xattr.c:1023 [inline]
>  filename_removexattr fs/xattr.c:1052 [inline]
>  path_removexattrat+0x35d/0x690 fs/xattr.c:1088
>  __do_sys_removexattr fs/xattr.c:1100 [inline]
>  __se_sys_removexattr fs/xattr.c:1097 [inline]
>  __x64_sys_removexattr+0x62/0x70 fs/xattr.c:1097
>  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: 0033:0x7fd613ef9bd9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fff6590fb28 EFLAGS: 00000246 ORIG_RAX: 00000000000000c5
> RAX: ffffffffffffffda RBX: 0000200000000340 RCX: 00007fd613ef9bd9
> RDX: ffffffffffffffb8 RSI: 0000200000000080 RDI: 0000200000000040
> RBP: 0000200000000380 R08: 0000555574d544c0 R09: 0000555574d544c0
> R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
> R13: 00007fff6590fd78 R14: 431bde82d7b634db R15: 0000200000000390
>  </TASK>
> INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 3.116 msecs
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ   for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status   for how to communicate with syzbot.
> 
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
> 
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
> 
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
> 
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
> 
> If you want to undo deduplication, reply with:
> #syz undup

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