syzbot


INFO: task hung in walk_component (4)

Status: auto-closed as invalid on 2022/06/09 10:18
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 290d, last: 267d
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 637d 637d 0/1 auto-closed as invalid on 2021/07/04 02:47
upstream INFO: task hung in walk_component (5) C inconclusive 12 9h45m 103d 0/24 upstream: reported C repro on 2022/08/22 12:38
upstream INFO: task hung in walk_component (3) 9 356d 527d 0/24 closed as invalid on 2022/02/07 19:19
linux-4.19 INFO: task hung in walk_component (2) 2 426d 480d 0/1 auto-closed as invalid on 2022/01/31 04:51
upstream INFO: task hung in walk_component (2) 31 630d 631d 22/24 fixed on 2021/04/09 19:46
android-44 INFO: task hung in walk_component 1 1314d 1314d 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 16d 122d 0/1 upstream: reported C repro on 2022/08/03 09:11
upstream INFO: task hung in walk_component 1 1603d 1603d 0/24 closed as invalid on 2018/09/05 12:51

Sample crash report:
INFO: task syz-executor.4:10542 blocked for more than 143 seconds.
      Not tainted 5.17.0-rc7-syzkaller-00200-gdda64ead7e82 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:29096 pid:10542 ppid:  3631 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4995 [inline]
 __schedule+0xa94/0x4910 kernel/sched/core.c:6304
 schedule+0xd2/0x260 kernel/sched/core.c:6377
 rwsem_down_read_slowpath+0x589/0xa70 kernel/locking/rwsem.c:1032
 __down_read_common kernel/locking/rwsem.c:1214 [inline]
 __down_read kernel/locking/rwsem.c:1223 [inline]
 down_read+0xe2/0x440 kernel/locking/rwsem.c:1463
 inode_lock_shared include/linux/fs.h:787 [inline]
 lookup_slow fs/namei.c:1723 [inline]
 walk_component+0x400/0x6a0 fs/namei.c:2020
 lookup_last fs/namei.c:2475 [inline]
 path_lookupat+0x1bb/0x860 fs/namei.c:2499
 filename_lookup+0x1c6/0x590 fs/namei.c:2528
 user_path_at_empty+0x42/0x60 fs/namei.c:2851
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x142/0x390 fs/stat.c:221
 vfs_fstatat fs/stat.c:243 [inline]
 vfs_lstat include/linux/fs.h:3287 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:398
 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: 0033:0x7f4a12355049
RSP: 002b:00007f4a10c88168 EFLAGS: 00000246 ORIG_RAX: 0000000000000006
RAX: ffffffffffffffda RBX: 00007f4a12468100 RCX: 00007f4a12355049
RDX: 0000000000000000 RSI: 0000000020000a40 RDI: 00000000200000c0
RBP: 00007f4a123af08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcfa31d7df R14: 00007f4a10c88300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8bb84ba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6460
2 locks held by getty/3274:
 #0: ffff88814ac49098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc90002b632e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2075
2 locks held by syz-executor.4/10530:
1 lock held by syz-executor.4/10542:
 #0: ffff888041a506e0 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:787 [inline]
 #0: ffff888041a506e0 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: lookup_slow fs/namei.c:1723 [inline]
 #0: ffff888041a506e0 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: walk_component+0x400/0x6a0 fs/namei.c:2020

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.17.0-rc7-syzkaller-00200-gdda64ead7e82 #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+0x1e6/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:369
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2952 Comm: klogd Not tainted 5.17.0-rc7-syzkaller-00200-gdda64ead7e82 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:lock_is_held_type+0xc/0x140 kernel/locking/lockdep.c:5667
Code: ac 89 89 44 24 04 e8 75 ee bb ff 0f 0b 8b 44 24 04 eb bd 66 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 56 41 55 41 bd ff ff ff ff <41> 54 55 53 48 83 ec 08 8b 0d 02 31 48 04 85 c9 0f 84 d9 00 00 00
RSP: 0018:ffffc90000dc0ba8 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffff88807dbbba80 RCX: 0000000000000001
RDX: 1ffffffff1771c46 RSI: 00000000ffffffff RDI: ffffffff8bb84ba0
RBP: ffff8880b9d39d00 R08: 0000000000000001 R09: ffffffff8ffc5947
R10: fffffbfff1ff8b28 R11: 0000000000000001 R12: 0000000000008ce7
R13: 00000000ffffffff R14: ffff88807dbbbad0 R15: ffff88807dbbba00
FS:  00007fd81a6ca800(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ce8a4d8b78 CR3: 000000007fb1f000 CR4: 0000000000350ee0
Call Trace:
 <IRQ>
 task_css_set include/linux/cgroup.h:481 [inline]
 task_dfl_cgroup include/linux/cgroup.h:550 [inline]
 cgroup_account_cputime include/linux/cgroup.h:795 [inline]
 update_curr+0x6c6/0x900 kernel/sched/fair.c:877
 enqueue_entity+0x299/0x1730 kernel/sched/fair.c:4272
 enqueue_task_fair+0x1ba/0x1b60 kernel/sched/fair.c:5620
 enqueue_task+0xad/0x3c0 kernel/sched/core.c:2010
 activate_task kernel/sched/core.c:2035 [inline]
 ttwu_do_activate+0x157/0x330 kernel/sched/core.c:3614
 ttwu_queue kernel/sched/core.c:3810 [inline]
 try_to_wake_up+0x508/0x1510 kernel/sched/core.c:4133
 autoremove_wake_function+0x12/0x140 kernel/sched/wait.c:416
 __wake_up_common+0x147/0x650 kernel/sched/wait.c:108
 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:138
 irq_work_single+0x120/0x270 kernel/irq_work.c:211
 irq_work_run_list kernel/irq_work.c:242 [inline]
 irq_work_run_list+0x91/0xc0 kernel/irq_work.c:225
 irq_work_run+0x54/0xd0 kernel/irq_work.c:251
 __sysvec_irq_work+0x95/0x3d0 arch/x86/kernel/irq_work.c:22
 sysvec_irq_work+0x8e/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x12/0x20 arch/x86/include/asm/idtentry.h:664
RIP: 0010:default_send_IPI_self+0x5d/0xe0 arch/x86/kernel/apic/ipi.c:243
Code: 1a f3 90 0f b6 45 00 84 c0 74 04 3c 03 7e 76 8b 04 25 00 c3 5f ff f6 c4 10 75 e6 81 cb 00 00 04 00 89 df 89 3c 25 00 c3 5f ff <5b> 5d c3 48 c7 c0 60 ea 58 8b 48 ba 00 00 00 00 00 fc ff df 48 c1
RSP: 0018:ffffc9000203f5c8 EFLAGS: 00000206
RAX: 00000000000008fb RBX: 00000000000400f6 RCX: ffffffff812a8eb3
RDX: 1ffffffff16b1d5b RSI: 0000000000000008 RDI: 00000000000400f6
RBP: fffffbffffebf860 R08: 0000000000000000 R09: ffffffff8d942507
R10: fffffbfff1b284a0 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000400cc0 R14: 00000000000000e8 R15: 0000000000000000
 arch_irq_work_raise+0x92/0x110 arch/x86/kernel/irq_work.c:31
 __irq_work_queue_local+0x15a/0x1b0 kernel/irq_work.c:102
 irq_work_queue kernel/irq_work.c:114 [inline]
 irq_work_queue+0x47/0x80 kernel/irq_work.c:106
 __kfence_alloc+0x164/0x1490 mm/kfence/core.c:887
 kfence_alloc include/linux/kfence.h:128 [inline]
 slab_alloc_node mm/slub.c:3148 [inline]
 kmem_cache_alloc_node+0x4b6/0x4f0 mm/slub.c:3266
 __alloc_skb+0x215/0x340 net/core/skbuff.c:414
 alloc_skb include/linux/skbuff.h:1158 [inline]
 alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:5956
 sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2586
 unix_dgram_sendmsg+0x414/0x1a10 net/unix/af_unix.c:1896
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:725
 __sys_sendto+0x21c/0x320 net/socket.c:2040
 __do_sys_sendto net/socket.c:2052 [inline]
 __se_sys_sendto net/socket.c:2048 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2048
 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: 0033:0x7fd81a8660ac
Code: 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 19 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 64 c3 0f 1f 00 55 48 83 ec 20 48 89 54 24 10
RSP: 002b:00007ffcd56be058 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd81a8660ac
RDX: 000000000000005d RSI: 0000559d39cbaf20 RDI: 0000000000000003
RBP: 0000559d39cb4910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000014
R13: 0000000000000001 R14: 00007fd81a9e177d R15: 00007ffcd56be168
 </TASK>
----------------
Code disassembly (best guess):
   0:	ac                   	lods   %ds:(%rsi),%al
   1:	89 89 44 24 04 e8    	mov    %ecx,-0x17fbdbbc(%rcx)
   7:	75 ee                	jne    0xfffffff7
   9:	bb ff 0f 0b 8b       	mov    $0x8b0b0fff,%ebx
   e:	44 24 04             	rex.R and $0x4,%al
  11:	eb bd                	jmp    0xffffffd0
  13:	66 66 2e 0f 1f 84 00 	data16 nopw %cs:0x0(%rax,%rax,1)
  1a:	00 00 00 00
  1e:	41 57                	push   %r15
  20:	41 56                	push   %r14
  22:	41 55                	push   %r13
  24:	41 bd ff ff ff ff    	mov    $0xffffffff,%r13d
* 2a:	41 54                	push   %r12 <-- trapping instruction
  2c:	55                   	push   %rbp
  2d:	53                   	push   %rbx
  2e:	48 83 ec 08          	sub    $0x8,%rsp
  32:	8b 0d 02 31 48 04    	mov    0x4483102(%rip),%ecx        # 0x448313a
  38:	85 c9                	test   %ecx,%ecx
  3a:	0f 84 d9 00 00 00    	je     0x119

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2022/03/11 10:13 upstream dda64ead7e82 9e8eaa75 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-selinux-root 2022/03/02 06:44 upstream 575115360652 45a13a73 .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-root 2022/02/23 20:04 upstream 5c1ee569660d 6e821dbf .config log report info INFO: task hung in walk_component
ci-upstream-kasan-gce-smack-root 2022/02/16 07:08 upstream 705d84a366cf 8b9ca619 .config log report info INFO: task hung in walk_component
* Struck through repros no longer work on HEAD.