syzbot


INFO: task hung in lock_mount (2)

Status: auto-closed as invalid on 2020/10/18 21:28
Reported-by: syzbot+67be3e7d02fd7eb20707@syzkaller.appspotmail.com
First crash: 1501d, last: 1495d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in lock_mount (4) 6 983d 1097d 0/1 auto-closed as invalid on 2022/03/15 09:18
android-49 INFO: task hung in lock_mount C 103 1814d 1932d 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 91d 91d 0/3 upstream: reported C repro on 2024/04/25 09:15
linux-4.19 INFO: task hung in lock_mount 5 1658d 1788d 0/1 auto-closed as invalid on 2020/05/09 01:51
upstream INFO: task hung in lock_mount nilfs C error error 1238 462d 2277d 22/27 fixed on 2023/06/08 14:41
android-44 INFO: task hung in lock_mount C 4 2211d 1930d 0/2 public: reported C repro on 2019/04/13 00:00
linux-4.19 INFO: task hung in lock_mount (3) 1 1261d 1261d 0/1 auto-closed as invalid on 2021/06/09 16:09
linux-4.14 INFO: task hung in lock_mount 2 1690d 1690d 0/1 auto-closed as invalid on 2020/04/07 06:26

Sample crash report:
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.1:8880 blocked for more than 140 seconds.
      Not tainted 4.19.128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D27368  8880   6566 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x8a2/0x1fc0 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
 rwsem_down_write_failed+0x3d4/0x7a0 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+0x8a/0x2e0 fs/namespace.c:2039
 do_add_mount+0x24/0x350 fs/namespace.c:2416
 do_new_mount fs/namespace.c:2483 [inline]
 do_mount+0x1596/0x2b50 fs/namespace.c:2799
 ksys_mount+0xd7/0x150 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ca59
Code: c7 04 24 ff ff ff ff 48 c7 44 24 08 ff ff ff ff 48 c7 44 24 10 00 00 00 00 48 8b 44 24 68 48 89 44 24 18 48 8b 44 24 70 48 89 <44> 24 20 48 8b 44 24 78 48 89 44 24 28 48 89 4c 24 30 0f 57 c0 0f
RSP: 002b:00007f57aa6a6c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004f6ce0 RCX: 000000000045ca59
RDX: 0000000020000140 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000078c040 R08: 0000000020000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000769 R14: 00000000004ca52b R15: 00007f57aa6a76d4

Showing all locks held in the system:
1 lock held by khungtaskd/1079:
 #0: 00000000e62b973d (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by syz-executor.1/8824:
 #0: 00000000779913d3 (&sb->s_type->i_mutex_key#24){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
 #0: 00000000779913d3 (&sb->s_type->i_mutex_key#24){++++}, at: do_last fs/namei.c:3326 [inline]
 #0: 00000000779913d3 (&sb->s_type->i_mutex_key#24){++++}, at: path_openat+0x1a04/0x2eb0 fs/namei.c:3537
1 lock held by syz-executor.1/8880:
 #0: 00000000779913d3 (&sb->s_type->i_mutex_key#24){++++}, at: inode_lock include/linux/fs.h:748 [inline]
 #0: 00000000779913d3 (&sb->s_type->i_mutex_key#24){++++}, at: lock_mount+0x8a/0x2e0 fs/namespace.c:2039

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

NMI backtrace for cpu 1
CPU: 1 PID: 1079 Comm: khungtaskd Not tainted 4.19.128-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/0x2fe lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb 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+0x962/0xe40 kernel/hung_task.c:287
 kthread+0x30b/0x410 kernel/kthread.c:246
 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: 3685 Comm: systemd-journal Not tainted 4.19.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_lockdep_rcu_enabled.part.0+0x26/0x50 kernel/rcu/update.c:254
Code: fe ff ff 90 48 b8 00 00 00 00 00 fc ff df 53 65 48 8b 1c 25 40 ee 01 00 48 8d bb 84 08 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 0f 8b 93 84 08 00
RSP: 0018:ffff8880940cfb50 EFLAGS: 00000807
RAX: dffffc0000000000 RBX: ffff8880940c00c0 RCX: 1ffffffff11f8958
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880940c0944
RBP: ffffffff8b8b9920 R08: 0000000000000001 R09: 0000000000000000
R10: fffff9400026d216 R11: ffffea00013690b7 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  00007fe252dfe8c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe2501f4020 CR3: 0000000094700000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0x2e7/0x3c0 kernel/locking/lockdep.c:3906
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152
 __debug_check_no_obj_freed lib/debugobjects.c:776 [inline]
 debug_check_no_obj_freed+0xc4/0x3e1 lib/debugobjects.c:817
 free_pages_prepare mm/page_alloc.c:1055 [inline]
 __free_pages_ok+0x225/0xd60 mm/page_alloc.c:1273
 slab_destroy+0x1f/0x50 mm/slab.c:1713
 slabs_destroy+0x6a/0x90 mm/slab.c:1729
 cache_flusharray mm/slab.c:3490 [inline]
 ___cache_free+0x277/0x380 mm/slab.c:3532
 qlink_free mm/kasan/quarantine.c:147 [inline]
 qlist_free_all+0x79/0x110 mm/kasan/quarantine.c:166
 quarantine_reduce+0x164/0x1a0 mm/kasan/quarantine.c:259
 kasan_kmalloc+0x95/0xc0 mm/kasan/kasan.c:538
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc mm/slab.c:3397 [inline]
 kmem_cache_alloc+0x111/0x370 mm/slab.c:3557
 prepare_creds+0x39/0x410 kernel/cred.c:255
 do_faccessat+0x94/0x7a0 fs/open.c:359
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fe2520ba9c7
Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffde23dab88 EFLAGS: 00000246 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00007ffde23ddaa0 RCX: 00007fe2520ba9c7
RDX: 00007fe252b2ba00 RSI: 0000000000000000 RDI: 00005613d84209a3
RBP: 00007ffde23dabc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffde23ddaa0 R15: 00007ffde23db0b0

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/20 21:28 linux-4.19.y 3fc898571b97 c655ec77 .config console log report ci2-linux-4-19
2020/06/14 15:19 linux-4.19.y 3fc898571b97 2a22c77a .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.