watchdog: BUG: soft lockup - CPU#1 stuck for 153s! [syz.1.13650:7845]
CPU#1 Utilization every 22s during lockup:
#1: 100% system, 1% softirq, 1% hardirq, 0% idle
#2: 100% system, 1% softirq, 1% hardirq, 0% idle
#3: 100% system, 0% softirq, 1% hardirq, 0% idle
#4: 100% system, 1% softirq, 1% hardirq, 0% idle
#5: 100% system, 1% softirq, 1% hardirq, 0% idle
Modules linked in:
CPU: 1 UID: 0 PID: 7845 Comm: syz.1.13650 Not tainted syzkaller #0 658fd523d4664e50339751640158cdc1077a64d7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:430 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x697/0xcc0 kernel/locking/qspinlock.c:508
Code: 01 00 00 c6 03 01 bb 00 80 ff ff 66 c7 84 24 90 00 00 00 00 01 48 8b 44 24 28 42 0f b6 04 30 84 c0 75 4c 80 3f 00 74 08 f3 90 <ff> c3 75 dd eb 59 be 02 00 00 00 e8 69 05 4d fc 48 8d bc 24 90 00
RSP: 0018:ffffc900068f7ac0 EFLAGS: 00000206
RAX: 0000000000000000 RBX: 00000000ffff9f24 RCX: ffff88812adf0000
RDX: ffff8881f6f50a54 RSI: 0000000000000003 RDI: ffffffff8720d604
RBP: ffffc900068f7bd0 R08: ffffffff8720d604 R09: 1ffffffff0e41ac0
R10: dffffc0000000000 R11: fffffbfff0e41ac1 R12: 0000000000000000
R13: 1ffffffff0e5cd9d R14: dffffc0000000000 R15: 1ffffffff0e41ac0
FS: 000055557d3f9500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005578c85b5df0 CR3: 0000000136fac000 CR4: 00000000003526b0
Call Trace:
<TASK>
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock include/linux/spinlock.h:187 [inline]
__raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
_raw_spin_lock+0x109/0x120 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
write_seqlock include/linux/seqlock.h:876 [inline]
lock_mount_hash fs/namespace.c:215 [inline]
mntput_no_expire+0x147/0x6c0 fs/namespace.c:1411
mntput+0x63/0xd0 fs/namespace.c:1466
__fput+0x5c5/0xa00 fs/file_table.c:440
____fput+0x20/0x30 fs/file_table.c:457
task_work_run+0x1e0/0x250 kernel/task_work.c:240
resume_user_mode_work+0x36/0x50 include/linux/resume_user_mode.h:50
exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x64/0xb0 kernel/entry/common.c:218
do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f613d38eec9
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:00007ffe59fa9428 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f613d5e7da0 RCX: 00007f613d38eec9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f613d5e7da0 R08: 0000000000000228 R09: 0000001e59fa971f
R10: 00007f613d5e7cb0 R11: 0000000000000246 R12: 00000000000b5b2a
R13: 00007f613d5e6090 R14: ffffffffffffffff R15: 00007ffe59fa9540
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7803 Comm: syz.2.13634 Not tainted syzkaller #0 658fd523d4664e50339751640158cdc1077a64d7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:next_peer fs/pnode.c:19 [inline]
RIP: 0010:do_make_slave fs/pnode.c:100 [inline]
RIP: 0010:change_mnt_propagation+0x13c/0xb00 fs/pnode.c:128
Code: 49 81 c4 d8 00 00 00 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 48 4e e7 ff 4d 8b 24 24 <49> 01 dc 4c 3b 65 c8 74 66 e8 76 fa 90 ff eb 99 4d 8d 7d 30 48 89
RSP: 0018:ffffc9000674f9c0 EFLAGS: 00000246
RAX: 1ffff11023380f2b RBX: ffffffffffffff28 RCX: dffffc0000000000
RDX: ffffc9001c69e000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000674fa10 R08: ffff8881548c666f R09: 0000000000000000
R10: ffff8881548c6660 R11: ffffed102a918cce R12: ffff888119c067d8
R13: ffff888110404000 R14: ffff888119c078a0 R15: ffff88812f7b48c0
FS: 00007ff7eab6f6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000014721e000 CR4: 00000000003526b0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
umount_tree+0xdfd/0xf70 fs/namespace.c:1803
attach_recursive_mnt+0x6df/0x21e0 fs/namespace.c:2549
graft_tree+0x157/0x1c0 fs/namespace.c:2684
do_loopback+0x364/0x4b0 fs/namespace.c:2816
path_mount+0x582/0x1050 fs/namespace.c:3858
do_mount fs/namespace.c:3877 [inline]
__do_sys_mount fs/namespace.c:4087 [inline]
__se_sys_mount+0x2bd/0x480 fs/namespace.c:4064
__x64_sys_mount+0xc3/0xf0 fs/namespace.c:4064
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: 0033:0x7ff7e9d8eec9
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:00007ff7eab6f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ff7e9fe6180 RCX: 00007ff7e9d8eec9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000000
RBP: 00007ff7e9e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000101091 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff7e9fe6218 R14: 00007ff7e9fe6180 R15: 00007ffd8845c458
</TASK>