syzbot


INFO: task hung in lock_mount

Status: public: reported C repro on 2019/04/11 08:44
Reported-by: syzbot+146d2f3d94cbaa8b0c9d@syzkaller.appspotmail.com
First crash: 2223d, last: 1809d
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 977d 1091d 0/1 auto-closed as invalid on 2022/03/15 09:18
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 1783d 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 2272d 22/27 fixed on 2023/06/08 14:41
linux-4.19 INFO: task hung in lock_mount (2) 2 1490d 1496d 0/1 auto-closed as invalid on 2020/10/18 21:28
android-44 INFO: task hung in lock_mount C 4 2206d 1925d 0/2 public: reported C repro on 2019/04/13 00:00
linux-4.19 INFO: task hung in lock_mount (3) 1 1256d 1256d 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

Sample crash report:
INFO: task syz-executor333:2136 blocked for more than 140 seconds.
      Not tainted 4.9.181+ #9
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor333 D28280  2136   2132 0x00000004
 0000000000000087 ffff8801cb8117c0 0000000000000000 ffff8801db721000
 ffff8801da6b2f80 ffff8801db721018 ffff8801ca03fae0 ffffffff82809e2e
 ffff8801cb8117c0 ffff8801cb8117c0 00ff8801ca03fa30 ffff8801db7218f0
Call Trace:
 [<00000000a71671d7>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<000000009769c186>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:549 [inline]
 [<000000009769c186>] rwsem_down_write_failed+0x3a3/0x750 kernel/locking/rwsem-xadd.c:578
 [<000000009b8139a7>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<000000006293c5ae>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<000000006293c5ae>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
 [<00000000e739f74b>] inode_lock include/linux/fs.h:771 [inline]
 [<00000000e739f74b>] lock_mount+0x8c/0x2c0 fs/namespace.c:2113
 [<0000000085c530ee>] do_add_mount+0x27/0x340 fs/namespace.c:2496
 [<00000000bd47e6bd>] do_new_mount fs/namespace.c:2563 [inline]
 [<00000000bd47e6bd>] do_mount+0x12ad/0x2970 fs/namespace.c:2871
 [<000000008073a4cc>] SYSC_mount fs/namespace.c:3087 [inline]
 [<000000008073a4cc>] SyS_mount+0xab/0x120 fs/namespace.c:3064
 [<00000000ec1484df>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<00000000c98374f0>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<0000000007438fb9>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<0000000007438fb9>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<000000002c5afc67>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by getty/2041:
 #0:  (&tty->ldisc_sem){++++++}, at: [<0000000024c567a9>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<00000000d286b6a5>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by syz-executor333/2136:
 #0:  (&type->i_mutex_dir_key#6){++++.+}, at: [<00000000e739f74b>] inode_lock include/linux/fs.h:771 [inline]
 #0:  (&type->i_mutex_dir_key#6){++++.+}, at: [<00000000e739f74b>] lock_mount+0x8c/0x2c0 fs/namespace.c:2113
2 locks held by syz-executor333/2137:
 #0:  (&fc->killsb){.+.+..}, at: [<000000005aa003b6>] fuse_notify_delete fs/fuse/dev.c:1553 [inline]
 #0:  (&fc->killsb){.+.+..}, at: [<000000005aa003b6>] fuse_notify fs/fuse/dev.c:1790 [inline]
 #0:  (&fc->killsb){.+.+..}, at: [<000000005aa003b6>] fuse_dev_do_write+0x1c55/0x22c0 fs/fuse/dev.c:1865
 #1:  (&type->i_mutex_dir_key#6){++++.+}, at: [<000000003e3309d5>] inode_lock include/linux/fs.h:771 [inline]
 #1:  (&type->i_mutex_dir_key#6){++++.+}, at: [<000000003e3309d5>] fuse_reverse_inval_entry+0xaf/0x670 fs/fuse/dir.c:1012
1 lock held by syz-executor333/2139:
 #0:  (&type->i_mutex_dir_key#6){++++.+}, at: [<00000000e739f74b>] inode_lock include/linux/fs.h:771 [inline]
 #0:  (&type->i_mutex_dir_key#6){++++.+}, at: [<00000000e739f74b>] lock_mount+0x8c/0x2c0 fs/namespace.c:2113
1 lock held by syz-executor333/2140:
 #0:  (&type->i_mutex_dir_key#6){++++.+}, at: [<00000000fbc4a954>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#6){++++.+}, at: [<00000000fbc4a954>] lookup_slow+0x160/0x480 fs/namei.c:1686

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.181+ #9
 ffff8801d98d7cc8 ffffffff81b57e21 0000000000000000 0000000000000000
 0000000000000000 ffffffff81099901 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b630bc 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<0000000032c3cbff>] __dump_stack lib/dump_stack.c:15 [inline]
 [<0000000032c3cbff>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000f3c8ffeb>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<00000000d3fedbcc>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000cb1fbe1d>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<000000001bb5c01a>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<000000001bb5c01a>] check_hung_task kernel/hung_task.c:126 [inline]
 [<000000001bb5c01a>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<000000001bb5c01a>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<0000000098cea0f6>] kthread+0x278/0x310 kernel/kthread.c:211
 [<000000007a9eada8>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2135 Comm: syz-executor333 Not tainted 4.9.181+ #9
task: 000000005baa50bf task.stack: 000000002be4b064
RIP: 0010:[<ffffffff8120bf70>] c [<000000004e2f07c1>] __lock_acquire+0x680/0x4350 kernel/locking/lockdep.c:3335
RSP: 0018:ffff8801cbbbf190  EFLAGS: 00000802
RAX: dffffc0000000000 RBX: 000000000000035d RCX: 1ffff10039702124
RDX: 1ffff10039702120 RSI: ffff8801cb810900 RDI: ffffffff83ccc7b0
RBP: ffff8801cbbbf318 R08: 0000000000000001 R09: ffff8801cb810920
R10: ffff8801cb810900 R11: 0000000000000000 R12: c2709b01d5d0a1d5
R13: 000000000000035d R14: 0000000000000002 R15: ffff8801cb810000
FS:  00007f61ffc3d700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5dd8965000 CR3: 00000001cbb25000 CR4: 00000000001606b0
Stack:
 ffff8801db721000c ffff8801cbbbf1a8c 0000000000000001c ffff8801cbbbf1c0c
 ffffffff82819b49c ffff8801db721000c ffff8801cbbbf218c ffffffff81169345c
 ffffffff81169317c ffffffff8281a511c ffffffff8281a505c ffffffff83ccc780c
Call Trace:
 [<0000000089548341>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756
 [<00000000938cdc47>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline]
 [<00000000938cdc47>] _raw_spin_lock_irqsave+0x50/0x70 kernel/locking/spinlock.c:159
 [<0000000004659bd2>] prepare_to_wait_event+0x5f/0x750 kernel/sched/wait.c:213
 [<000000004dfeeb30>] request_wait_answer+0x249/0x820 fs/fuse/dev.c:477
 [<00000000a313c6e4>] __fuse_request_send+0x109/0x1b0 fs/fuse/dev.c:498
 [<00000000dd5b5a0d>] fuse_request_send+0x63/0x70 fs/fuse/dev.c:511
 [<0000000025c914a2>] fuse_simple_request+0x2c4/0x660 fs/fuse/dev.c:569
 [<000000003c7e923a>] fuse_lookup_name+0x260/0x640 fs/fuse/dir.c:369
 [<0000000078bf99ab>] fuse_lookup+0xec/0x3b0 fs/fuse/dir.c:407
 [<000000001039f245>] lookup_slow+0x24b/0x480 fs/namei.c:1709
 [<000000001d6fc6fe>] walk_component+0x71e/0xce0 fs/namei.c:1825
 [<000000008b7acf16>] lookup_last fs/namei.c:2307 [inline]
 [<000000008b7acf16>] path_lookupat.isra.0+0x18f/0x3f0 fs/namei.c:2324
 [<00000000b3cee808>] filename_lookup+0x1a1/0x3b0 fs/namei.c:2358
 [<00000000f70fe0ea>] user_path_at_empty+0x43/0x50 fs/namei.c:2619
 [<00000000a59b0aaa>] user_path_at include/linux/namei.h:55 [inline]
 [<00000000a59b0aaa>] vfs_fstatat+0xc6/0x170 fs/stat.c:106
 [<00000000fa3bf20d>] vfs_stat fs/stat.c:123 [inline]
 [<00000000fa3bf20d>] SYSC_newstat fs/stat.c:270 [inline]
 [<00000000fa3bf20d>] SyS_newstat+0x94/0x100 fs/stat.c:266
 [<00000000ec1484df>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<00000000c98374f0>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: c3c c02 c00 c0f c85 cae c2a c00 c00 c4d c8b ca7 ca0 c08 c00 c00 c45 c31 cdb c45 c85 cf6 c41 c0f c94 cc3 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c4c c89 cd2 c48 cc1 cea c03 c<80> c3c c02 c00 c0f c85 c4b c29 c00 c00 c48 c8b c94 c24 c80 c00 c00 c00 c4d c89 c22 c

Crashes (103):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/06/17 19:04 https://android.googlesource.com/kernel/common android-4.9 0c1ee05e1e72 442206d7 .config console log report syz C ci-android-49-kasan-gce-root
2018/06/18 06:31 https://android.googlesource.com/kernel/common android-4.9 a4230beab30a 27c5f59f .config console log report syz C ci-android-49-kasan-gce-root
2018/06/30 05:44 https://android.googlesource.com/kernel/common android-4.9 00a0bcbfcfb6 dba0b50e .config console log report syz C ci-android-49-kasan-gce-386
2019/08/06 14:30 https://android.googlesource.com/kernel/common android-4.9 712595fe9d6c 6affd8e8 .config console log report ci-android-49-kasan-gce-root
2018/12/01 20:07 https://android.googlesource.com/kernel/common android-4.9 db71418d4a90 5a581673 .config console log report ci-android-49-kasan-gce-root
2018/08/30 07:38 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 6c7e9d3d .config console log report ci-android-49-kasan-gce-root
2018/08/29 22:27 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 4937cb2b .config console log report ci-android-49-kasan-gce-root
2018/08/29 00:33 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c b771b17e .config console log report ci-android-49-kasan-gce-root
2018/08/28 21:51 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c b771b17e .config console log report ci-android-49-kasan-gce-root
2018/08/28 04:50 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 7ef1de9e .config console log report ci-android-49-kasan-gce-root
2018/08/27 07:26 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 758cd203 .config console log report ci-android-49-kasan-gce-root
2018/08/26 12:48 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 758cd203 .config console log report ci-android-49-kasan-gce-root
2018/08/25 13:46 https://android.googlesource.com/kernel/common android-4.9 09eb2ba5ed0c 9be5aa1d .config console log report ci-android-49-kasan-gce-root
2018/08/25 04:00 https://android.googlesource.com/kernel/common android-4.9 6a1b5923548a 9b0f5c75 .config console log report ci-android-49-kasan-gce-root
2018/08/24 23:49 https://android.googlesource.com/kernel/common android-4.9 6a1b5923548a 9b0f5c75 .config console log report ci-android-49-kasan-gce-root
2018/08/24 12:22 https://android.googlesource.com/kernel/common android-4.9 520d10d31ca4 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/24 03:46 https://android.googlesource.com/kernel/common android-4.9 7fa8c15e72a4 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/24 02:18 https://android.googlesource.com/kernel/common android-4.9 7fa8c15e72a4 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/23 17:04 https://android.googlesource.com/kernel/common android-4.9 8dd3fc2ed765 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/23 02:46 https://android.googlesource.com/kernel/common android-4.9 8dd3fc2ed765 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/21 13:03 https://android.googlesource.com/kernel/common android-4.9 54068d61e7d8 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/20 21:46 https://android.googlesource.com/kernel/common android-4.9 54068d61e7d8 95b5c82b .config console log report ci-android-49-kasan-gce-root
2018/08/20 07:45 https://android.googlesource.com/kernel/common android-4.9 54068d61e7d8 2dc4378f .config console log report ci-android-49-kasan-gce-root
2018/08/19 23:19 https://android.googlesource.com/kernel/common android-4.9 54068d61e7d8 2dc4378f .config console log report ci-android-49-kasan-gce-root
2018/08/19 19:23 https://android.googlesource.com/kernel/common android-4.9 54068d61e7d8 2dc4378f .config console log report ci-android-49-kasan-gce-root
2018/08/19 03:27 https://android.googlesource.com/kernel/common android-4.9 54068d61e7d8 de20bcbb .config console log report ci-android-49-kasan-gce-root
2018/08/17 02:07 https://android.googlesource.com/kernel/common android-4.9 f85543ba3c54 9ccc1d45 .config console log report ci-android-49-kasan-gce-root
2018/08/15 23:07 https://android.googlesource.com/kernel/common android-4.9 f85543ba3c54 9ccc1d45 .config console log report ci-android-49-kasan-gce-root
2018/08/15 05:36 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 0e6dcb88 .config console log report ci-android-49-kasan-gce-root
2018/08/15 04:16 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 0e6dcb88 .config console log report ci-android-49-kasan-gce-root
2018/08/14 19:22 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 5084a625 .config console log report ci-android-49-kasan-gce-root
2018/08/13 10:59 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/13 08:23 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/13 05:51 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/12 08:41 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/12 02:19 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/11 22:05 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/11 11:35 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/11 10:10 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/11 02:42 https://android.googlesource.com/kernel/common android-4.9 9dc978d43ec7 7a88b141 .config console log report ci-android-49-kasan-gce-root
2018/08/10 17:31 https://android.googlesource.com/kernel/common android-4.9 92e87041ed2d 1fb62d58 .config console log report ci-android-49-kasan-gce-root
2018/08/09 09:26 https://android.googlesource.com/kernel/common android-4.9 856452b4f22e 2eeda842 .config console log report ci-android-49-kasan-gce-root
2018/08/09 06:25 https://android.googlesource.com/kernel/common android-4.9 856452b4f22e 2eeda842 .config console log report ci-android-49-kasan-gce-root
2018/08/08 08:07 https://android.googlesource.com/kernel/common android-4.9 47b77b8d01c4 1beb8136 .config console log report ci-android-49-kasan-gce-root
2018/08/08 06:12 https://android.googlesource.com/kernel/common android-4.9 47b77b8d01c4 1beb8136 .config console log report ci-android-49-kasan-gce-root
* Struck through repros no longer work on HEAD.