INFO: task hung in open_tree

Status: auto-obsoleted due to no activity on 2025/10/21 08:51
Reported-by: syzbot+496604500c1bdcbf1ba2@syzkaller.appspotmail.com
First crash: 377d, last: 377d

Sample crash report:
INFO: task syz.1.3922:12168 blocked for more than 122 seconds.
      Not tainted 6.12.30-syzkaller-gfc2476d0896a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.3922      state:D stack:0     pid:12168 tgid:12165 ppid:7158   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:1229
 __down_write_common kernel/locking/rwsem.c:1373 [inline]
 __down_write kernel/locking/rwsem.c:1382 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1649
 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: 0033:0x7f87d878e9a9
RSP: 002b:00007f87d9656038 EFLAGS: 00000246 ORIG_RAX: 00000000000001ac
RAX: ffffffffffffffda RBX: 00007f87d89b6160 RCX: 00007f87d878e9a9
RDX: 0000000000089901 RSI: 0000200000000640 RDI: ffffffffffffff9c
RBP: 00007f87d8810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f87d89b6160 R15: 00007ffdeb6886a8
 </TASK>
INFO: task syz.5.3923:12171 blocked for more than 124 seconds.
      Not tainted 6.12.30-syzkaller-gfc2476d0896a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.3923      state:D stack:0     pid:12171 tgid:12170 ppid:9616   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:1229
 __down_write_common kernel/locking/rwsem.c:1373 [inline]
 __down_write kernel/locking/rwsem.c:1382 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1649
 inode_lock include/linux/fs.h:815 [inline]
 do_lock_mount+0x201/0x520 fs/namespace.c:2617
 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: 0033:0x7fe90578e9a9
RSP: 002b:00007fe9065b7038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe9059b5fa0 RCX: 00007fe90578e9a9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000380
RBP: 00007fe905810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002125099 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe9059b5fa0 R15: 00007fffdbec6fd8
 </TASK>
INFO: task syz.5.3923:12172 blocked for more than 125 seconds.
      Not tainted 6.12.30-syzkaller-gfc2476d0896a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.3923      state:D stack:0     pid:12172 tgid:12170 ppid:9616   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:1229
 __down_write_common kernel/locking/rwsem.c:1373 [inline]
 __down_write kernel/locking/rwsem.c:1382 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1649
 namespace_lock fs/namespace.c:1714 [inline]
 copy_mnt_ns+0x12f/0x8e0 fs/namespace.c:3951
 create_new_namespaces+0xd9/0x720 kernel/nsproxy.c:78
 copy_namespaces+0x25d/0x2b0 kernel/nsproxy.c:179
 copy_process+0x126d/0x3220 kernel/fork.c:2408
 kernel_clone+0x23f/0x830 kernel/fork.c:2818
 __do_sys_clone kernel/fork.c:2963 [inline]
 __se_sys_clone kernel/fork.c:2947 [inline]
 __x64_sys_clone+0x18c/0x1f0 kernel/fork.c:2947
 x64_sys_call+0x2b3c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:57
 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: 0033:0x7fe90578e9a9
RSP: 002b:00007fe906595fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fe9059b6080 RCX: 00007fe90578e9a9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000b21e0000
RBP: 00007fe905810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe9059b6080 R15: 00007fffdbec6fd8
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.30-syzkaller-gfc2476d0896a #0 e1e9364838a23ddd1cd40ddd4d9250930b5d8506
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12166 Comm: syz.1.3922 Not tainted 6.12.30-syzkaller-gfc2476d0896a #0 e1e9364838a23ddd1cd40ddd4d9250930b5d8506
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:lock_mnt_tree fs/namespace.c:2311 [inline]
RIP: 0010:attach_recursive_mnt+0x1d7f/0x21c0 fs/namespace.c:2535
Code: 97 24 eb ff 4d 89 ee 48 8b 84 24 98 00 00 00 49 39 07 0f 84 96 01 00 00 4d 8d 7e 30 4c 89 7c 24 18 49 c1 ef 03 43 0f b6 04 27 <84> c0 0f 85 31 01 00 00 41 8b 5e 30 41 89 dd 41 83 e5 40 31 ff 44
RSP: 0018:ffffc9000359fb00 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: ffff88816387a950 RCX: 0000000000080000
RDX: ffffc90015371000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000359fc48 R08: ffff8881529d812f R09: 0000000000000000
R10: ffff8881529d8120 R11: ffffed102a53b026 R12: dffffc0000000000
R13: ffff888163c56fc0 R14: ffff88816387a8c0 R15: 1ffff1102c70f51e
FS:  00007f87d96986c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c139d6d58 CR3: 000000015777e000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 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: 0033:0x7f87d878e9a9
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:00007f87d9698038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f87d89b5fa0 RCX: 00007f87d878e9a9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000380
RBP: 00007f87d8810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002125099 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f87d89b5fa0 R15: 00007ffdeb6886a8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/23 08:41 android16-6.12 fc2476d0896a e1dd4f22 .config console log report info ci2-android-6-12-rust INFO: task hung in open_tree
* Struck through repros no longer work on HEAD.