syzbot


INFO: task hung in walk_component (3)

Status: closed as invalid on 2022/02/07 19:19
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 531d, last: 360d
similar bugs (8):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in walk_component 1 641d 641d 0/1 auto-closed as invalid on 2021/07/04 02:47
upstream INFO: task hung in walk_component (5) C inconclusive 12 4d19h 107d 0/24 upstream: reported C repro on 2022/08/22 12:38
linux-4.19 INFO: task hung in walk_component (2) 2 430d 485d 0/1 auto-closed as invalid on 2022/01/31 04:51
upstream INFO: task hung in walk_component (2) 31 635d 635d 22/24 fixed on 2021/04/09 19:46
upstream INFO: task hung in walk_component (4) 4 271d 294d 0/24 auto-closed as invalid on 2022/06/09 10:18
android-44 INFO: task hung in walk_component 1 1318d 1318d 0/2 auto-closed as invalid on 2019/10/25 08:50
linux-4.19 INFO: task hung in walk_component (3) C error 3 20d 126d 0/1 upstream: reported C repro on 2022/08/03 09:11
upstream INFO: task hung in walk_component 1 1608d 1608d 0/24 closed as invalid on 2018/09/05 12:51

Sample crash report:
INFO: task syz-executor.1:21824 blocked for more than 143 seconds.
      Not tainted 5.16.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:29568 pid:21824 ppid:  3638 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4972 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6253
 schedule+0xd2/0x260 kernel/sched/core.c:6326
 rwsem_down_read_slowpath+0x589/0xa70 kernel/locking/rwsem.c:1041
 __down_read_common kernel/locking/rwsem.c:1223 [inline]
 __down_read kernel/locking/rwsem.c:1232 [inline]
 down_read+0xe2/0x440 kernel/locking/rwsem.c:1472
 inode_lock_shared include/linux/fs.h:793 [inline]
 lookup_slow fs/namei.c:1673 [inline]
 walk_component+0x400/0x6a0 fs/namei.c:1970
 lookup_last fs/namei.c:2425 [inline]
 path_lookupat+0x1bb/0x860 fs/namei.c:2449
 filename_lookup+0x1c6/0x590 fs/namei.c:2478
 user_path_at_empty+0x42/0x60 fs/namei.c:2801
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3328 [inline]
 __do_sys_mount fs/namespace.c:3539 [inline]
 __se_sys_mount fs/namespace.c:3516 [inline]
 __x64_sys_mount+0x1ea/0x300 fs/namespace.c:3516
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4319f44e99
RSP: 002b:00007f4318878168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f431a058100 RCX: 00007f4319f44e99
RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 00007f4319f9f031 R08: 0000000020000280 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff644c08cf R14: 00007f4318878300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8bb83d20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
2 locks held by getty/3281:
 #0: ffff888023456098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002b962e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
3 locks held by kworker/u4:7/3735:
1 lock held by udevd/3858:
3 locks held by udevd/3873:
 #0: ffff8880b9c39a98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:478
 #1: ffff88802260ec30 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:818 [inline]
 #1: ffff88802260ec30 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: lock_rename+0x225/0x280 fs/namei.c:2915
 #2: ffff88807f5ec558 (&ep->lock){...-}-{2:2}, at: ep_poll_callback+0x75/0xf90 fs/eventpoll.c:1136
1 lock held by udevd/7509:
1 lock held by udevd/7521:
1 lock held by udevd/18501:
 #0: ffff8880b9d39a98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:478
2 locks held by kworker/u4:26/20816:
 #0: ffff8880b9d39a98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:478
 #1: ffff8880b9d279c8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x3a6/0x490 kernel/sched/psi.c:880
2 locks held by syz-executor.1/21820:
1 lock held by syz-executor.1/21824:
 #0: ffff88803daa06e0 (&type->i_mutex_dir_key#9){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:793 [inline]
 #0: ffff88803daa06e0 (&type->i_mutex_dir_key#9){++++}-{3:3}, at: lookup_slow fs/namei.c:1673 [inline]
 #0: ffff88803daa06e0 (&type->i_mutex_dir_key#9){++++}-{3:3}, at: walk_component+0x400/0x6a0 fs/namei.c:1970

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:295
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7509 Comm: udevd Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200
Code: 48 89 ef 5d e9 31 22 46 00 5d be 03 00 00 00 e9 d6 33 63 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 8b 05 b9 c4 8a 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b
RSP: 0018:ffffc900055475a0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000009 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88807e11d700 RDI: 0000000000000003
RBP: ffff888018c79b80 R08: 0000000000000000 R09: 0000000000000009
R10: ffffffff83a33b57 R11: 0000000000000010 R12: 0000000000000002
R13: 00000000000000b1 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f0ba4e22840(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f43188ba9e0 CR3: 000000001c116000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 tomoyo_domain_quota_is_ok+0x31a/0x550 security/tomoyo/util.c:1092
 tomoyo_supervisor+0x2f2/0xf00 security/tomoyo/common.c:2089
 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline]
 tomoyo_path_permission security/tomoyo/file.c:587 [inline]
 tomoyo_path_permission+0x270/0x3a0 security/tomoyo/file.c:573
 tomoyo_check_open_permission+0x33e/0x380 security/tomoyo/file.c:777
 tomoyo_file_open security/tomoyo/tomoyo.c:311 [inline]
 tomoyo_file_open+0xa3/0xd0 security/tomoyo/tomoyo.c:306
 security_file_open+0x45/0xb0 security/security.c:1635
 do_dentry_open+0x353/0x1250 fs/open.c:809
 do_open fs/namei.c:3426 [inline]
 path_openat+0x1cad/0x2750 fs/namei.c:3559
 do_filp_open+0x1aa/0x400 fs/namei.c:3586
 do_sys_openat2+0x16d/0x4d0 fs/open.c:1212
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_openat fs/open.c:1244 [inline]
 __se_sys_openat fs/open.c:1239 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1239
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f0ba4f79697
Code: 25 00 00 41 00 3d 00 00 41 00 74 37 64 8b 04 25 18 00 00 00 85 c0 75 5b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 85 00 00 00 48 83 c4 68 5d 41 5c c3 0f 1f
RSP: 002b:00007ffe3e8edb00 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055b562af2810 RCX: 00007f0ba4f79697
RDX: 0000000000080000 RSI: 000055b562b12cc0 RDI: 00000000ffffff9c
RBP: 000055b562b12cc0 R08: 000055b562b12cc0 R09: 00007f0ba5049a60
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 0000000000000701 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	48 89 ef             	mov    %rbp,%rdi
   3:	5d                   	pop    %rbp
   4:	e9 31 22 46 00       	jmpq   0x46223a
   9:	5d                   	pop    %rbp
   a:	be 03 00 00 00       	mov    $0x3,%esi
   f:	e9 d6 33 63 02       	jmpq   0x26333ea
  14:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
  1a:	48 8b be b0 01 00 00 	mov    0x1b0(%rsi),%rdi
  21:	e8 b4 ff ff ff       	callq  0xffffffda
  26:	31 c0                	xor    %eax,%eax
  28:	c3                   	retq
  29:	90                   	nop
* 2a:	65 8b 05 b9 c4 8a 7e 	mov    %gs:0x7e8ac4b9(%rip),%eax        # 0x7e8ac4ea <-- trapping instruction
  31:	89 c1                	mov    %eax,%ecx
  33:	48 8b 34 24          	mov    (%rsp),%rsi
  37:	81 e1 00 01 00 00    	and    $0x100,%ecx
  3d:	65                   	gs
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

Crashes (9):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2021/12/12 03:54 upstream 6f513529296f 49ca1f59 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-root 2021/12/01 05:33 upstream f080815fdb3e 80270552 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-smack-root 2021/11/16 05:26 upstream 8ab774587903 83f5c9b5 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-root 2021/10/28 01:10 upstream 1fc596a56b33 373bf66b .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-smack-root 2021/10/15 21:39 upstream ec681c53f8d2 0c5d9412 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-selinux-root 2021/09/25 19:40 upstream 7d42e9818258 8cac236e .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-selinux-root 2021/08/03 03:23 upstream c500bee1c5b2 6c236867 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-smack-root 2021/06/24 07:13 upstream 7266f2030eb0 fe4ab389 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-root 2021/06/24 06:55 upstream 7266f2030eb0 fe4ab389 .config log report info INFO: task hung in walk_component
* Struck through repros no longer work on HEAD.