syzbot


INFO: task hung in lock_mount (4)

Status: auto-closed as invalid on 2022/03/15 09:18
Reported-by: syzbot+183b1203a047848d6123@syzkaller.appspotmail.com
First crash: 1091d, last: 977d
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 INFO: task hung in lock_mount C 103 1808d 1926d 0/3 public: reported C repro on 2019/04/11 08:44
linux-5.15 INFO: task hung in lock_mount origin:upstream C error 1 85d 85d 0/3 upstream: reported C repro on 2024/04/25 09:15
linux-4.19 INFO: task hung in lock_mount 5 1652d 1782d 0/1 auto-closed as invalid on 2020/05/09 01:51
upstream INFO: task hung in lock_mount nilfs C error error 1238 457d 2271d 22/27 fixed on 2023/06/08 14:41
linux-4.19 INFO: task hung in lock_mount (2) 2 1489d 1495d 0/1 auto-closed as invalid on 2020/10/18 21:28
android-44 INFO: task hung in lock_mount C 4 2206d 1924d 0/2 public: reported C repro on 2019/04/13 00:00
linux-4.19 INFO: task hung in lock_mount (3) 1 1255d 1255d 0/1 auto-closed as invalid on 2021/06/09 16:09
linux-4.14 INFO: task hung in lock_mount 2 1684d 1685d 0/1 auto-closed as invalid on 2020/04/07 06:26
upstream INFO: task can't die in lock_mount fs C 75 970d 1307d 0/27 closed as dup on 2021/01/18 10:01
upstream INFO: task can't die in iget5_locked fuse 7 1240d 1265d 20/27 fixed on 2021/04/09 19:46

Sample crash report:
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-executor.2:1568 blocked for more than 140 seconds.
      Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D27920  1568  29328 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
 rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
 call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
 __down_write arch/x86/include/asm/rwsem.h:142 [inline]
 down_write+0x4f/0x90 kernel/locking/rwsem.c:72
 inode_lock include/linux/fs.h:748 [inline]
 lock_mount+0xcc/0x4a0 fs/namespace.c:2075
 do_add_mount+0x73/0x560 fs/namespace.c:2439
 do_new_mount fs/namespace.c:2506 [inline]
 do_mount+0x1976/0x2f50 fs/namespace.c:2822
 ksys_mount+0xcf/0x130 fs/namespace.c:3038
 __do_sys_mount fs/namespace.c:3052 [inline]
 __se_sys_mount fs/namespace.c:3049 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3049
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f0fca60fae9
Code: Bad RIP value.
RSP: 002b:00007f0fc7b64188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0fca723020 RCX: 00007f0fca60fae9
RDX: 0000000020000b80 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 00007f0fca669f6d R08: 0000000020000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcc8f1bfef R14: 00007f0fc7b64300 R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1570:
 #0: 00000000b3a55ff7 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by in:imklog/7798:
 #0: 000000002832a01b (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by agetty/17433:
 #0: 00000000c40e128c (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
 #1: 00000000dda25cfe (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
2 locks held by syz-executor.2/1517:
 #0: 000000006b890c8e (sb_writers#26){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
 #0: 000000006b890c8e (sb_writers#26){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360
 #1: 0000000043f9fbfc (&sb->s_type->i_mutex_key#34){++++}, at: inode_lock include/linux/fs.h:748 [inline]
 #1: 0000000043f9fbfc (&sb->s_type->i_mutex_key#34){++++}, at: vfs_setxattr+0xc7/0x270 fs/xattr.c:254
1 lock held by syz-executor.2/1568:
 #0: 0000000043f9fbfc (&sb->s_type->i_mutex_key#34){++++}, at: inode_lock include/linux/fs.h:748 [inline]
 #0: 0000000043f9fbfc (&sb->s_type->i_mutex_key#34){++++}, at: lock_mount+0xcc/0x4a0 fs/namespace.c:2075
1 lock held by systemd-tmpfile/1638:
 #0: 0000000083904da7 (&type->i_mutex_dir_key#3){++++}, at: iterate_dir+0xd2/0x5c0 fs/readdir.c:41

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

NMI backtrace for cpu 1
CPU: 1 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0x995/0x3ff0 kernel/locking/lockdep.c:3442
Code: 74 08 3c 03 0f 8e 98 25 00 00 41 8b 85 80 08 00 00 83 c0 01 83 f8 2f 41 89 85 80 08 00 00 0f 87 cb 07 00 00 3b 05 6b 72 46 0b <41> bf 01 00 00 00 0f 86 e8 f7 ff ff 89 05 59 72 46 0b e9 dd f7 ff
RSP: 0018:ffff8880b5a47a68 EFLAGS: 00000093
RAX: 0000000000000003 RBX: a6f1d9c08eafd477 RCX: c2cc60ee0328b757
RDX: 1ffff11016b46d48 RSI: 000000005a4ba51f RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000e9a03af8 R09: 0000000000000002
R10: ffff8880b5a36a98 R11: 0000000000000000 R12: c2cc60ee0328b757
R13: ffff8880b5a361c0 R14: ffff8880b5a36ab0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc37de7a000 CR3: 00000000af105000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 rcu_lock_acquire include/linux/rcupdate.h:242 [inline]
 rcu_read_lock include/linux/rcupdate.h:627 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline]
 batadv_nc_worker+0x12d/0xd50 net/batman-adv/network-coding.c:730
 process_one_work+0x864/0x1570 kernel/workqueue.c:2153
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
----------------
Code disassembly (best guess):
   0:	74 08                	je     0xa
   2:	3c 03                	cmp    $0x3,%al
   4:	0f 8e 98 25 00 00    	jle    0x25a2
   a:	41 8b 85 80 08 00 00 	mov    0x880(%r13),%eax
  11:	83 c0 01             	add    $0x1,%eax
  14:	83 f8 2f             	cmp    $0x2f,%eax
  17:	41 89 85 80 08 00 00 	mov    %eax,0x880(%r13)
  1e:	0f 87 cb 07 00 00    	ja     0x7ef
  24:	3b 05 6b 72 46 0b    	cmp    0xb46726b(%rip),%eax        # 0xb467295
* 2a:	41 bf 01 00 00 00    	mov    $0x1,%r15d <-- trapping instruction
  30:	0f 86 e8 f7 ff ff    	jbe    0xfffff81e
  36:	89 05 59 72 46 0b    	mov    %eax,0xb467259(%rip)        # 0xb467295
  3c:	e9                   	.byte 0xe9
  3d:	dd f7                	(bad)
  3f:	ff                   	.byte 0xff

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/11/15 09:17 linux-4.19.y 3f8a27f9e27b 75b04091 .config console log report info ci2-linux-4-19 INFO: task hung in lock_mount
2021/11/02 04:18 linux-4.19.y 3f8a27f9e27b 098b5d53 .config console log report info ci2-linux-4-19 INFO: task hung in lock_mount
2021/10/12 08:43 linux-4.19.y e34184f53363 838e7e2c .config console log report info ci2-linux-4-19 INFO: task hung in lock_mount
2021/08/25 08:22 linux-4.19.y 59456c9cc40c b599f2fc .config console log report info ci2-linux-4-19 INFO: task hung in lock_mount
2021/08/12 11:02 linux-4.19.y 5c66974a6304 6972b106 .config console log report info ci2-linux-4-19 INFO: task hung in lock_mount
2021/07/24 02:17 linux-4.19.y 4938296e03bd bc5f1d88 .config console log report info ci2-linux-4-19 INFO: task hung in lock_mount
* Struck through repros no longer work on HEAD.