INFO: task hung in do_change_type

Status: auto-obsoleted due to no activity on 2025/10/17 01:07
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+15605c3f4c9c3df360e0@syzkaller.appspotmail.com
First crash: 378d, last: 378d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/07/21 lts (merge base) e0e2f7824338 syz [report] INFO: task hung in dissolve_on_fput
2025/07/21 upstream (ToT) 89be9a83ccf1 syz [report] INFO: task hung in do_change_type
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/10/14 04:44 15m retest repro android16-6.12 OK log
2025/08/03 07:24 19m retest repro android16-6.12 report log

Sample crash report:
INFO: task syz.5.168:1014 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.5.168       state:D stack:0     pid:1014  tgid:1013  ppid:861    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: 0033:0x7f391f58e9a9
RSP: 002b:00007f392047b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f391f7b5fa0 RCX: 00007f391f58e9a9
RDX: 0000000000000000 RSI: 00002000000005c0 RDI: 0000000000000000
RBP: 00007f391f610d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000100000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f391f7b5fa0 R15: 00007ffe24fafa88
 </TASK>
INFO: task syz.5.168:1015 blocked for more than 123 seconds.
      Not tainted 6.12.30-syzkaller-g2e58e85c038f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.168       state:D stack:0     pid:1015  tgid:1013  ppid:861    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: 0033:0x7f391f58e9a9
RSP: 002b:00007f392045a038 EFLAGS: 00000246 ORIG_RAX: 00000000000001ac
RAX: ffffffffffffffda RBX: 00007f391f7b6080 RCX: 00007f391f58e9a9
RDX: 0000000000089901 RSI: 0000200000000640 RDI: ffffffffffffff9c
RBP: 00007f391f610d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f391f7b6080 R15: 00007ffe24fafa88
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.30-syzkaller-g2e58e85c038f #0 c5e7ad78b71ddb211d6a9cda70735ca8545dcbc5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2c7/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 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: 1012 Comm: syz.6.167 Not tainted 6.12.30-syzkaller-g2e58e85c038f #0 c5e7ad78b71ddb211d6a9cda70735ca8545dcbc5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:do_make_slave fs/pnode.c:101 [inline]
RIP: 0010:change_mnt_propagation+0xff/0xb00 fs/pnode.c:128
Code: 58 e7 ff 4d 8b 2e 48 c7 c3 28 ff ff ff 4d 89 fc 4d 8d 74 24 20 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 4c 89 f7 e8 67 58 e7 ff 4d 39 2e 0f 84 8f 00 00 00 49 81 c4
RSP: 0018:ffffc900040e79c0 EFLAGS: 00000246
RAX: 1ffff1102569a384 RBX: ffffffffffffff28 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000040000 RDI: 0000000000100000
RBP: ffffc900040e7a10 R08: ffff888140180d6f R09: 0000000000000000
R10: ffff888140180d60 R11: ffffed10280301ae R12: ffff88812b4d1c00
R13: ffff888110771220 R14: ffff88812b4d1c20 R15: ffff888137460e00
FS:  00007f3c18bca6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f11451901a0 CR3: 0000000114aa6000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 umount_tree+0xdfd/0xf70 fs/namespace.c:1807
 attach_recursive_mnt+0x6df/0x21c0 fs/namespace.c:2548
 graft_tree+0x157/0x1c0 fs/namespace.c:2683
 do_loopback+0x364/0x4b0 fs/namespace.c:2798
 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: 0033:0x7f3c17d8e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3c18bca038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f3c17fb6240 RCX: 00007f3c17d8e9a9
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000200000000240
RBP: 00007f3c17e10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000080700a R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f3c17fb6240 R15: 00007fff4505e098
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/19 01:04 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 do_change_type
* Struck through repros no longer work on HEAD.