INFO: task hung in dissolve_on_fput

Status: premoderation: reported syz repro on 2025/07/19 05:19
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+2d60952cdec46272d328@syzkaller.appspotmail.com
First crash: 380d, last: 73d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/07/20 lts (merge base) e0e2f7824338 syz [report] BUG: soft lockup in x64_sys_call
2025/07/20 upstream (ToT) f4a40a4282f4 syz [report] INFO: task hung in put_mnt_ns
▶ ▼ Last patch testing requests (5)
Created Duration User Patch Repo Result
2026/05/19 08:17 16m retest repro android16-6.12 log
2026/03/01 16:34 18m retest repro android16-6.12 report log
2025/12/21 14:50 4m retest repro android16-6.12 error
2025/10/12 10:14 13m retest repro android16-6.12 report log
2025/08/02 08:07 15m retest repro android16-6.12 report log

Sample crash report:
INFO: task syz.5.89:748 blocked for more than 122 seconds.
      Not tainted 6.12.30-syzkaller-g2e58e85c038f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.89        state:D stack:0     pid:748   tgid:737   ppid:677    flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7942
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1227
 __down_write_common kernel/locking/rwsem.c:1371 [inline]
 __down_write kernel/locking/rwsem.c:1380 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1647
 namespace_lock fs/namespace.c:1714 [inline]
 dissolve_on_fput+0x2d/0x110 fs/namespace.c:2211
 __fput+0x867/0xa00 fs/file_table.c:441
 ____fput+0x20/0x30 fs/file_table.c:459
 task_work_run+0x1e3/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9b4/0x2630 kernel/exit.c:944
 do_group_exit+0x22a/0x300 kernel/exit.c:1094
 get_signal+0x139d/0x14f0 kernel/signal.c:2934
 arch_do_signal_or_restart+0x96/0x720 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f5ec898e9a9
RSP: 002b:00007f5ec9732038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007f5ec8bb6320 RCX: 00007f5ec898e9a9
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000200000000240
RBP: 00007f5ec8a10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000080700a R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f5ec8bb6320 R15: 00007ffe570918a8
 </TASK>
INFO: task syz.4.91:752 blocked for more than 125 seconds.
      Not tainted 6.12.30-syzkaller-g2e58e85c038f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.91        state:D stack:0     pid:752   tgid:751   ppid:673    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7942
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1227
 __down_write_common kernel/locking/rwsem.c:1371 [inline]
 __down_write kernel/locking/rwsem.c:1380 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1647
 namespace_lock fs/namespace.c:1714 [inline]
 do_lock_mount+0x20d/0x520 fs/namespace.c:2618
 lock_mount fs/namespace.c:2662 [inline]
 do_loopback+0x256/0x4b0 fs/namespace.c:2782
 path_mount+0x582/0x1050 fs/namespace.c:3840
 do_mount fs/namespace.c:3859 [inline]
 __do_sys_mount fs/namespace.c:4069 [inline]
 __se_sys_mount+0x2bd/0x480 fs/namespace.c:4046
 __x64_sys_mount+0xc3/0xf0 fs/namespace.c:4046
 x64_sys_call+0x2021/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f1d1738e9a9
RSP: 002b:00007f1d18158038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1d175b5fa0 RCX: 00007f1d1738e9a9
RDX: 0000000000000000 RSI: 0000200000000300 RDI: 0000200000000380
RBP: 00007f1d17410d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002125099 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1d175b5fa0 R15: 00007ffdf299e2f8
 </TASK>
INFO: task syz.4.91:753 blocked for more than 127 seconds.
      Not tainted 6.12.30-syzkaller-g2e58e85c038f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.91        state:D stack:0     pid:753   tgid:751   ppid:673    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7942
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1227
 __down_write_common kernel/locking/rwsem.c:1371 [inline]
 __down_write kernel/locking/rwsem.c:1380 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1647
 namespace_lock fs/namespace.c:1714 [inline]
 do_change_type+0x11e/0x510 fs/namespace.c:2721
 path_mount+0x43b/0x1050 fs/namespace.c:3842
 do_mount fs/namespace.c:3859 [inline]
 __do_sys_mount fs/namespace.c:4069 [inline]
 __se_sys_mount+0x2bd/0x480 fs/namespace.c:4046
 __x64_sys_mount+0xc3/0xf0 fs/namespace.c:4046
 x64_sys_call+0x2021/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f1d1738e9a9
RSP: 002b:00007f1d18137038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1d175b6080 RCX: 00007f1d1738e9a9
RDX: 0000000000000000 RSI: 00002000000005c0 RDI: 0000000000000000
RBP: 00007f1d17410d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000100000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f1d175b6080 R15: 00007ffdf299e2f8
 </TASK>
INFO: task syz.4.91:754 blocked for more than 129 seconds.
      Not tainted 6.12.30-syzkaller-g2e58e85c038f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.91        state:D stack:0     pid:754   tgid:751   ppid:673    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7942
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1227
 __down_write_common kernel/locking/rwsem.c:1371 [inline]
 __down_write kernel/locking/rwsem.c:1380 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1647
 namespace_lock fs/namespace.c:1714 [inline]
 open_detached_copy fs/namespace.c:2821 [inline]
 __do_sys_open_tree fs/namespace.c:2887 [inline]
 __se_sys_open_tree+0x34a/0x8e0 fs/namespace.c:2849
 __x64_sys_open_tree+0x7f/0xa0 fs/namespace.c:2849
 x64_sys_call+0x2d58/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:429
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f1d1738e9a9
RSP: 002b:00007f1d18116038 EFLAGS: 00000246 ORIG_RAX: 00000000000001ac
RAX: ffffffffffffffda RBX: 00007f1d175b6160 RCX: 00007f1d1738e9a9
RDX: 0000000000089901 RSI: 0000200000000640 RDI: ffffffffffffff9c
RBP: 00007f1d17410d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f1d175b6160 R15: 00007ffdf299e2f8
 </TASK>
INFO: task syz.4.91:755 blocked for more than 131 seconds.
      Not tainted 6.12.30-syzkaller-g2e58e85c038f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.91        state:D stack:0     pid:755   tgid:751   ppid:673    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x132b/0x1e00 kernel/sched/core.c:7789
 __schedule_loop kernel/sched/core.c:7870 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7885
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7942
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1227
 __down_write_common kernel/locking/rwsem.c:1371 [inline]
 __down_write kernel/locking/rwsem.c:1380 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1647
 namespace_lock fs/namespace.c:1714 [inline]
 do_lock_mount+0x20d/0x520 fs/namespace.c:2618
 lock_mount fs/namespace.c:2662 [inline]
 do_loopback+0x256/0x4b0 fs/namespace.c:2782
 path_mount+0x582/0x1050 fs/namespace.c:3840

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/19 05:18 android16-6.12 2e58e85c038f 7117feec .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in dissolve_on_fput
2026/05/22 13:34 android16-6.12 9d40b257ba08 5f091fcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in dissolve_on_fput
* Struck through repros no longer work on HEAD.