syzbot


INFO: task hung in user_get_super (2)

Status: upstream: reported C repro on 2023/11/19 11:27
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+ba09f4a317431df6cddf@syzkaller.appspotmail.com
First crash: 1083d, last: 4h10m
Cause bisection: failed (error log, bisect log)
  
Discussions (6)
Title Replies (including bot) Last reply
[syzbot] Monthly fs report (Jul 2024) 0 (1) 2024/07/18 07:59
[syzbot] Monthly fs report (Mar 2024) 0 (1) 2024/03/16 12:09
[syzbot] Monthly fs report (Feb 2024) 0 (1) 2024/02/12 21:31
[syzbot] Monthly fs report (Dec 2023) 0 (1) 2023/12/12 22:02
[syzbot] Test 0 (1) 2023/11/19 12:31
[syzbot] [fs?] INFO: task hung in user_get_super (2) 0 (1) 2023/11/19 11:27
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in user_get_super 1 2 1074d 1081d 0/3 auto-obsoleted due to no activity on 2023/08/15 03:00
linux-5.15 INFO: task hung in user_get_super 1 6 891d 1069d 0/3 auto-obsoleted due to no activity on 2024/01/25 03:23
linux-5.15 INFO: task hung in user_get_super (2) 1 1 725d 725d 0/3 auto-obsoleted due to no activity on 2024/07/08 17:00
linux-5.15 INFO: task hung in user_get_super (4) origin:lts-only 1 C done 4 5d12h 312d 0/3 upstream: reported C repro on 2025/05/17 12:04
linux-6.1 INFO: task hung in user_get_super (2) origin:lts-only 1 C inconclusive 28 70d 856d 0/3 upstream: reported C repro on 2023/11/20 11:19
upstream INFO: task hung in user_get_super fs 1 1 1183d 1183d 0/29 auto-obsoleted due to no activity on 2023/04/06 01:17
linux-5.15 INFO: task hung in user_get_super (3) 1 9 569d 614d 0/3 auto-obsoleted due to no activity on 2024/12/12 06:40
Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/09/18 07:15 21m retest repro upstream OK log
2025/06/07 21:03 16m retest repro upstream report log
2024/11/20 16:04 29m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci OK log
2023/11/19 12:31 20m tintinm2017@gmail.com https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master report log

Sample crash report:
INFO: task syz.0.721:11926 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.721       state:D stack:28712 pid:11926 tgid:11922 ppid:11206  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 __rwbase_read_lock+0xc3/0x180 kernel/locking/rwbase_rt.c:114
 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline]
 __down_read kernel/locking/rwsem.c:1466 [inline]
 down_read+0x132/0x200 kernel/locking/rwsem.c:1539
 __super_lock fs/super.c:60 [inline]
 super_lock+0x2d6/0x3d0 fs/super.c:122
 user_get_super+0xc8/0x120 fs/super.c:1001
 quotactl_block fs/quota/quota.c:889 [inline]
 __do_sys_quotactl fs/quota/quota.c:955 [inline]
 __se_sys_quotactl+0x540/0x9e0 fs/quota/quota.c:917
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75cadfc799
RSP: 002b:00007f75c9035028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f75cb076090 RCX: 00007f75cadfc799
RDX: 0000000000000000 RSI: 0000200000000080 RDI: ffffffff80000600
RBP: 00007f75cae92c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75cb076128 R14: 00007f75cb076090 R15: 00007ffe1d7cad28
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8ddcba80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8ddcba80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8ddcba80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:3/57:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000123fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000123fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8f15c178 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by kworker/u8:4/68:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000153fc40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000153fc40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
2 locks held by dhcpcd/5463:
2 locks held by getty/5560:
 #0: ffff88803746d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by syz-executor/7189:
5 locks held by kworker/u8:1/9248:
 #0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc900055cfc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc900055cfc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8f14d9c0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675
 #3: ffffffff8f15c178 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0xa00 net/core/dev.c:13055
 #4: ffff888019c4f238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3d/0x130 fs/kernfs/dir.c:1717
1 lock held by udevd/11609:
1 lock held by syz.0.721/11926:
 #0: ffff88803aa960d0 (&type->s_umount_key#82){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
 #0: ffff88803aa960d0 (&type->s_umount_key#82){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
1 lock held by udevd/12851:
2 locks held by syz-executor/13492:
 #0: ffffffff8f6c37e8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8f6c37e8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8f6c37e8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8f15c178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8f15c178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8f15c178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071
3 locks held by syz.5.953/13666:
1 lock held by syz.2.951/13668:
4 locks held by syz.6.954/13670:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13668 Comm: syz.2.951 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0033:0x7f852f4e3b20
Code: 1f 84 00 00 00 00 00 0f 1f 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 47 0f b6 0c 08 45 84 c9 74 08 45 88 0c 00 49 8b 47 10 <48> 83 c0 01 49 89 47 10 83 e9 01 73 d3 41 81 fe 00 01 00 00 0f 85
RSP: 002b:00007f852d885470 EFLAGS: 00000246
RAX: 0000000000f07c34 RBX: 00007f852d885530 RCX: 00000000000000c1
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007f852d8855d0
RBP: 0000000000000102 R08: 00007f8525466000 R09: 0000000000000000
R10: 0000000000000000 R11: 00007f852d885540 R12: 0000000000000001
R13: 00007f852f6e2620 R14: 0000000000000000 R15: 00007f852d8855d0
FS:  00007f852d8866c0 GS:  0000000000000000

Crashes (1461):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/26 03:24 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/26 00:52 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/25 23:33 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/25 21:58 upstream bbeb83d3182a c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/25 14:02 upstream bbeb83d3182a 8ee77f7d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/25 10:44 upstream bbeb83d3182a 8ee77f7d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/25 08:03 upstream bbeb83d3182a 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/25 05:33 upstream e3c33bc767b5 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/24 16:15 upstream c369299895a5 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/24 13:49 upstream c369299895a5 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/24 06:49 upstream c369299895a5 baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/24 04:59 upstream c369299895a5 baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/24 03:06 upstream c369299895a5 baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/23 23:20 upstream c369299895a5 4933dba2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/23 19:40 upstream c369299895a5 4933dba2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/23 15:01 upstream c369299895a5 4933dba2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/23 13:18 upstream c369299895a5 4933dba2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/23 07:09 upstream 8d8bd2a5aa98 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/22 20:07 upstream 8d8bd2a5aa98 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/22 10:50 upstream 113ae7b4decc 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/22 04:05 upstream 113ae7b4decc 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/22 01:36 upstream 113ae7b4decc 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/21 12:10 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/21 10:21 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/21 08:43 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/21 06:27 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/21 04:17 upstream 165160265e4b 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/21 03:10 upstream 165160265e4b ac6f1dff .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/20 09:54 upstream 0e4f8f1a3d08 2f245add .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/20 01:42 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 23:51 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 22:02 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 13:55 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 10:25 upstream 8a30aeb0d1b4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 06:54 upstream 8a30aeb0d1b4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 05:21 upstream 8a30aeb0d1b4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/19 02:37 upstream 8a30aeb0d1b4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/18 20:41 upstream a989fde763f4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/18 13:23 upstream a989fde763f4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/18 09:07 upstream f0caa1d49cc0 c8810548 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/17 22:27 upstream f0caa1d49cc0 c8810548 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/17 18:47 upstream 2d1373e4246d c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/05 17:49 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in user_get_super
2025/04/24 15:38 upstream a79be02bba5c 9882047a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs INFO: task hung in user_get_super
2024/11/06 13:07 upstream 2e1b3cc9d7f7 3a465482 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in user_get_super
2024/05/25 04:34 upstream 0b32d436c015 a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in user_get_super
2023/06/13 10:32 upstream fb054096aea0 749afb64 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2023/06/11 14:39 upstream 022ce8862dff 7086cdb9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in user_get_super
2023/05/30 13:15 upstream 8b817fded42d cf184559 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in user_get_super
2026/03/23 09:53 linux-next 785f0eb2f85d 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in user_get_super
2025/07/12 07:48 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci ec4801305969 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in user_get_super
2023/11/19 11:26 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8de1e7afcc1c cb976f63 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-gce-arm64 INFO: task hung in user_get_super
* Struck through repros no longer work on HEAD.