syzbot


INFO: task hung in grab_super (4)

Status: auto-obsoleted due to no activity on 2025/05/10 07:53
Subsystems: nfs
[Documentation on labels]
First crash: 106d, last: 91d
Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in grab_super 4 2385d 2223d 0/1 auto-closed as invalid on 2019/04/28 15:34
linux-4.14 INFO: task hung in grab_super C error 241 898d 2214d 0/1 upstream: reported C repro on 2019/04/19 12:37
android-414 INFO: task hung in grab_super (2) 2 2124d 2146d 0/1 auto-closed as invalid on 2019/11/15 12:55
android-49 INFO: task hung in grab_super 1 2463d 2463d 0/3 auto-closed as invalid on 2019/02/22 13:19
linux-5.15 INFO: task hung in grab_super 1 405d 405d 0/3 auto-obsoleted due to no activity on 2024/07/10 06:22
upstream INFO: task hung in grab_super udf C 209 840d 2489d 0/28 closed as dup on 2018/07/18 11:42
linux-6.1 INFO: task hung in grab_super 1 401d 401d 0/3 auto-obsoleted due to no activity on 2024/07/15 01:06
linux-4.19 INFO: task hung in grab_super vfs udf C error 249 822d 2215d 0/1 upstream: reported C repro on 2019/04/18 03:33
upstream INFO: task hung in grab_super (2) fs 1 705d 705d 0/28 auto-obsoleted due to no activity on 2023/09/05 02:19
upstream INFO: task hung in grab_super (3) nilfs ext4 20 398d 551d 0/28 auto-obsoleted due to no activity on 2024/07/07 20:46
android-49 INFO: task hung in grab_super (2) 1 2091d 2091d 0/3 auto-closed as invalid on 2019/12/19 00:51

Sample crash report:
INFO: task syz.7.2466:16878 blocked for more than 143 seconds.
      Tainted: G     U             6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.2466      state:D stack:27696 pid:16878 tgid:16877 ppid:12745  task_flags:0x400140 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6856
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913
 rwsem_down_write_slowpath+0x539/0x12a0 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1d8/0x200 kernel/locking/rwsem.c:1578
 __super_lock fs/super.c:56 [inline]
 super_lock+0x176/0x3f0 fs/super.c:120
 super_lock_excl fs/super.c:145 [inline]
 grab_super+0xab/0x430 fs/super.c:530
 sget_fc+0x5c3/0xb90 fs/super.c:800
 vfs_get_super fs/super.c:1275 [inline]
 get_tree_keyed+0x59/0x1d0 fs/super.c:1317
 vfs_get_tree+0x8b/0x340 fs/super.c:1814
 do_new_mount fs/namespace.c:3560 [inline]
 path_mount+0x6e1/0x1f00 fs/namespace.c:3887
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount fs/namespace.c:4088 [inline]
 __x64_sys_mount+0x28f/0x310 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2c5718cde9
RSP: 002b:00007f2c58059038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2c573a5fa0 RCX: 00007f2c5718cde9
RDX: 0000400000000140 RSI: 0000400000000080 RDI: 0000000000000000
RBP: 00007f2c5720e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2c573a5fa0 R15: 00007ffd273bee68
 </TASK>
INFO: task syz.7.2466:16883 blocked for more than 144 seconds.
      Tainted: G     U             6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.2466      state:D stack:27680 pid:16883 tgid:16877 ppid:12745  task_flags:0x400140 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6856
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730
 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
 nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1386
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
 deactivate_super+0xde/0x100 fs/super.c:506
 cleanup_mnt+0x222/0x450 fs/namespace.c:1413
 task_work_run+0x14e/0x250 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2c5718cde9
RSP: 002b:00007f2c58038038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffec RBX: 00007f2c573a6080 RCX: 00007f2c5718cde9
RDX: 0000400000000140 RSI: 0000400000000040 RDI: 0000000000000000
RBP: 00007f2c5720e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2c573a6080 R15: 00007ffd273bee68
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e1bc140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e1bc140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1bc140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746
2 locks held by getty/13584:
 #0: ffff888031dbc0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000c50b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211
2 locks held by kworker/u8:25/14270:
2 locks held by syz.1.2073/15189:
 #0: ffffffff8ff79030 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8e5bda88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xe3/0x1b40 fs/nfsd/nfsctl.c:1922
1 lock held by syz.7.2466/16878:
 #0: ffff8880347f20e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880347f20e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: super_lock+0x176/0x3f0 fs/super.c:120
2 locks held by syz.7.2466/16883:
 #0: ffff8880347f20e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880347f20e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880347f20e0 (&type->s_umount_key#49){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:505
 #1: ffffffff8e5bda88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
1 lock held by syz.9.2886/18651:
4 locks held by syz.0.2896/18706:
2 locks held by syz.9.2918/18793:
2 locks held by syz.9.2936/18849:
2 locks held by syz.9.2937/18851:
1 lock held by syz.9.2937/18853:
 #0: ffff8880b863ed58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:598

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G     U             6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0xf62/0x12b0 kernel/hung_task.c:399
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 14270 Comm: kworker/u8:25 Tainted: G     U             6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:trace_irq_enable.constprop.0+0x3d/0x140 include/trace/events/preemptirq.h:40
Code: 07 0f 87 03 01 00 00 89 db be 08 00 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 10 e6 5f 90 e8 3b 39 5b 00 48 0f a3 1d a3 47 9f 0e <0f> 82 a2 00 00 00 5b 5d 41 5c c3 cc cc cc cc 48 89 fb 48 c7 c5 8c
RSP: 0018:ffffc9000458fa78 EFLAGS: 00000047
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81c09e65
RDX: fffffbfff20bfcc3 RSI: 0000000000000008 RDI: ffffffff905fe610
RBP: 000000000003da8c R08: 0000000000000000 R09: fffffbfff20bfcc2
R10: ffffffff905fe617 R11: 0000000000000002 R12: ffffffff8b156290
R13: ffff888061000a00 R14: 0000000000000000 R15: ffff8880324eedc0
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000021000 CR3: 00000000328a8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 trace_hardirqs_on+0x26/0x40 kernel/trace/trace_preemptirq.c:73
 __local_bh_enable_ip+0xa4/0x120 kernel/softirq.c:394
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_nc_purge_paths+0x1c6/0x390 net/batman-adv/network-coding.c:471
 batadv_nc_worker+0x94a/0x1060 net/batman-adv/network-coding.c:722
 process_one_work+0x958/0x1b30 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/09 07:44 upstream 9946eaf552b1 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in grab_super
2025/01/26 00:13 upstream 0f8e26b38d7a 9fbd772e .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in grab_super
* Struck through repros no longer work on HEAD.