INFO: task hung in deactivate_super (3)

Status: upstream: reported C repro on 2024/05/27 12:00
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+4ae63a93dbe1440d6ba3@syzkaller.appspotmail.com
First crash: 809d, last: 17d
Fix commit to backport (bisect log) :
tree: upstream
commit fb6f20ecb121cef4d7946f834a6ee867c4e21b4a
Author: Jan Kara <jack@suse.cz>
Date: Thu Oct 17 10:28:23 2024 +0000

  reiserfs: The last commit

  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/01/05 linux-6.1.y (ToT) 7dc732d24ff7 C [report] INFO: task hung in deactivate_super
2025/01/05 upstream (ToT) ab75170520d4 C Didn't crash
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 INFO: task hung in deactivate_super 1 3 2954d 2972d 0/3 auto-closed as invalid on 2019/02/22 12:34
linux-6.1 INFO: task hung in deactivate_super 1 4 1092d 1141d 0/3 auto-obsoleted due to no activity on 2023/11/26 12:17
linux-4.14 INFO: task hung in deactivate_super 1 1 2664d 2664d 0/1 auto-closed as invalid on 2019/10/25 08:42
upstream INFO: task hung in deactivate_super exfat 1 36 2775d 2878d 0/29 closed as dup on 2018/10/27 13:17
upstream INFO: task hung in deactivate_super (2) jfs 1 syz, C inconclusive done 121 895d 1234d 25/29 fixed on 2024/04/08 19:23
upstream INFO: task hung in deactivate_super (3) prio:high hfs 1 syz, C done error 109 3d20h 765d 0/29 upstream: reported C repro on 2024/07/11 01:05
linux-5.15 INFO: task hung in deactivate_super 1 4 1089d 1178d 0/3 auto-obsoleted due to no activity on 2023/11/29 20:11
linux-6.1 INFO: task hung in deactivate_super (2) 1 1 913d 913d 0/3 auto-obsoleted due to no activity on 2024/05/24 05:27
linux-5.15 INFO: task hung in deactivate_super (2) missing-backport origin:upstream 1 syz, C done 5 20d 657d 0/3 upstream: reported C repro on 2024/10/27 03:45
linux-4.19 INFO: task hung in deactivate_super 1 4 1266d 1367d 0/1 upstream: reported on 2022/11/16 10:48
linux-6.6 INFO: task hung in deactivate_super 1 1 186d 186d 0/2 auto-obsoleted due to no activity on 2026/05/20 17:25
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/01/11 04:26 8h25m fix candidate upstream OK (1) job log

Sample crash report:
INFO: task syz-executor415:4266 blocked for more than 143 seconds.
      Not tainted 6.1.130-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor415 state:D stack:26184 pid:4266  ppid:4261   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 rwsem_down_write_slowpath+0xea1/0x14b0 kernel/locking/rwsem.c:1189
 deactivate_super+0xa9/0xe0 fs/super.c:362
 cleanup_mnt+0x490/0x520 fs/namespace.c:1186
 task_work_run+0x246/0x300 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fec295ca477
RSP: 002b:00007fff726053d8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fec295ca477
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff72605490
RBP: 00007fff72605490 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000206 R12: 00007fff726064f0
R13: 000055558d4396c0 R14: 0000000000000001 R15: 431bde82d7b634db
 </TASK>
INFO: task syz-executor415:4281 blocked for more than 143 seconds.
      Not tainted 6.1.130-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor415 state:D stack:26808 pid:4281  ppid:4265   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6695
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1094 [inline]
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x6ff/0xa30 kernel/locking/rwsem.c:1522
 iterate_supers+0xac/0x1e0 fs/super.c:755
 quota_sync_all fs/quota/quota.c:69 [inline]
 __do_sys_quotactl fs/quota/quota.c:937 [inline]
 __se_sys_quotactl+0x347/0x770 fs/quota/quota.c:916
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fec295c9219
RSP: 002b:00007fff726064c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fec295c9219
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fff726064f0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff726064ec
R13: 00007fff72606550 R14: 00004000000000c0 R15: 431bde82d7b634db
 </TASK>
INFO: task syz-executor415:4282 blocked for more than 143 seconds.
      Not tainted 6.1.130-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor415 state:D stack:26560 pid:4282  ppid:4263   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6695
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1094 [inline]
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x6ff/0xa30 kernel/locking/rwsem.c:1522
 iterate_supers+0xac/0x1e0 fs/super.c:755
 quota_sync_all fs/quota/quota.c:69 [inline]
 __do_sys_quotactl fs/quota/quota.c:937 [inline]
 __se_sys_quotactl+0x347/0x770 fs/quota/quota.c:916
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fec295c9219
RSP: 002b:00007fff726064c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fec295c9219
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fff726064f0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff726064ec
R13: 00007fff72606550 R14: 00004000000000c0 R15: 431bde82d7b634db
 </TASK>
INFO: task syz-executor415:4283 blocked for more than 144 seconds.
      Not tainted 6.1.130-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor415 state:D stack:26808 pid:4283  ppid:4264   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6695
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1094 [inline]
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x6ff/0xa30 kernel/locking/rwsem.c:1522
 iterate_supers+0xac/0x1e0 fs/super.c:755
 quota_sync_all fs/quota/quota.c:69 [inline]
 __do_sys_quotactl fs/quota/quota.c:937 [inline]
 __se_sys_quotactl+0x347/0x770 fs/quota/quota.c:916
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fec295c9219
RSP: 002b:00007fff726064c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fec295c9219
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fff726064f0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff726064ec
R13: 00007fff72606550 R14: 00004000000000c0 R15: 431bde82d7b634db
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32e850 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32f050 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by getty/4009:
 #0: ffff88814d049098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x54a/0x1620 drivers/tty/n_tty.c:2198
1 lock held by syz-executor415/4266:
 #0: ffff88807afd40e0 (&type->s_umount_key#62){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362
6 locks held by syz-executor415/4280:
1 lock held by syz-executor415/4281:
 #0: ffff88807afd40e0 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:755
1 lock held by syz-executor415/4282:
 #0: ffff88807afd40e0 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:755
1 lock held by syz-executor415/4283:
 #0: ffff88807afd40e0 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:755

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1ca/0x430 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted 6.1.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x7b/0x290 mm/kasan/generic.c:189
Code: 00 00 00 00 fc ff df 4f 8d 34 1a 4c 89 f5 4c 29 cd 48 83 fd 10 7f 26 48 85 ed 0f 84 3a 01 00 00 49 f7 d2 49 01 da 41 80 39 00 <0f> 85 c4 01 00 00 49 ff c1 49 ff c2 75 ee e9 1d 01 00 00 45 89 cf
RSP: 0018:ffffc900001079d8 EFLAGS: 00000246
RAX: f87eca5aaafed901 RBX: 1ffffffff1a7999c RCX: ffffffff8aba699b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d3ccce0
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1a7999c
R10: ffffffffffffffff R11: dffffc0000000001 R12: ffffc90000107aa0
R13: dffffc0000000000 R14: fffffbfff1a7999d R15: ffffffff81b5e2f6
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556cf1c95600 CR3: 000000000d08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 atomic_long_read include/linux/atomic/atomic-instrumented.h:1265 [inline]
 __mutex_unlock_slowpath+0xeb/0x750 kernel/locking/mutex.c:916
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xbf/0x480 mm/kfence/core.c:805
 process_one_work+0x917/0x1260 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.274 msecs

Crashes (25):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/10 05:45 linux-6.1.y 6ae7ac5c4251 163f510d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/03/10 02:23 linux-6.1.y 6ae7ac5c4251 163f510d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/02/09 23:23 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (clean fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/01/04 15:55 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/06/08 07:49 linux-6.1.y 58485ff1a74f 4826c28e .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/02/10 09:05 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/11/07 23:51 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/03/17 17:09 linux-6.1.y 344a09659766 948c34e4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/03/01 05:40 linux-6.1.y 3a8358583626 67cf5345 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/02/05 05:53 linux-6.1.y 0cbb5f65e52f 5896748e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/02/05 05:51 linux-6.1.y 0cbb5f65e52f 5896748e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/01/21 02:02 linux-6.1.y f4f677285b38 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/12/28 04:16 linux-6.1.y 563edd786f0a d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/12/13 16:52 linux-6.1.y e4d90d63d385 3547e30f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/11/28 05:29 linux-6.1.y e4d90d63d385 5df23865 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/11/23 03:13 linux-6.1.y e4d90d63d385 68da6d95 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/10/08 23:22 linux-6.1.y aa4cd140bba5 402f1df0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/09/26 13:00 linux-6.1.y e526b12bf916 0d19f247 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/09/12 07:27 linux-6.1.y 5ca5b389fddf d94c83d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/08/14 16:45 linux-6.1.y 117ac406ba90 e6b88e20 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/07/30 11:12 linux-6.1.y c1cec4dad96b 5187fc86 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2026/07/28 20:02 linux-6.1.y dc5c83b7f5f8 edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in deactivate_super
2026/06/24 07:22 linux-6.1.y fdb6fcb41cc7 042555ff .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in deactivate_super
2024/12/08 03:31 linux-6.1.y e4d90d63d385 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in deactivate_super
2024/05/27 12:00 linux-6.1.y 88690811da69 761766e6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in deactivate_super
* Struck through repros no longer work on HEAD.