watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.8.9294:28505]
CPU#0 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, 1% 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: 0 UID: 0 PID: 28505 Comm: syz.8.9294 Not tainted syzkaller #0 68071847e78a8b5e73ab1b858b320f4e6b4f981b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_native_safe_halt+0x17/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc b8 93 7d 33 b0 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 32 3a 00 f3 0f 1e fa 55 48 89 e5 fb f4 <5d> e9 d3 54 02 00 cc cc cc b8 00 00 00 00 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90001f37850 EFLAGS: 000002d3
RAX: ffffffff81439535 RBX: 0000000000000003 RCX: ffff888120b88000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: ffffc90001f37850 R08: ffffffff8720d604 R09: 1ffffffff0e41ac0
R10: dffffc0000000000 R11: fffffbfff0e41ac1 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff920003e6f0c
FS: 00005555912ee500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f64e37c5f98 CR3: 000000012d830000 CR4: 00000000003526b0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline]
kvm_wait+0x1ba/0x220 arch/x86/kernel/kvm.c:1064
pv_wait arch/x86/include/asm/paravirt.h:596 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline]
__pv_queued_spin_lock_slowpath+0x78d/0xcc0 kernel/locking/qspinlock.c:508
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
simple_release_fs+0xb4/0xe0 fs/libfs.c:1086
remove_one+0x368/0x3e0 fs/debugfs/inode.c:810
simple_recursive_removal+0x71f/0x8f0 fs/libfs.c:631
debugfs_remove+0x5a/0x80 fs/debugfs/inode.c:832
kvm_destroy_vm_debugfs virt/kvm/kvm_main.c:1038 [inline]
kvm_destroy_vm virt/kvm/kvm_main.c:1317 [inline]
kvm_put_kvm+0x130/0x12c0 virt/kvm/kvm_main.c:1392
kvm_vm_release+0x47/0x70 virt/kvm/kvm_main.c:1415
__fput+0x1fe/0xa00 fs/file_table.c:429
____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: 0033:0x7f19e0d8eec9
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:00007ffdddb6c5d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f19e0fe7da0 RCX: 00007f19e0d8eec9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f19e0fe7da0 R08: 00000000000001ac R09: 00000018ddb6c8cf
R10: 00007f19e0fe7cb0 R11: 0000000000000246 R12: 000000000009e8a6
R13: 00007ffdddb6c6d0 R14: ffffffffffffffff R15: 00007ffdddb6c6f0
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 28506 Comm: syz.8.9294 Not tainted syzkaller #0 68071847e78a8b5e73ab1b858b320f4e6b4f981b
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+0x112/0xb00 fs/pnode.c:128
Code: 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 77 4e e7 ff 4d 39 2e 0f 84 8f 00 00 00 <49> 81 c4 d8 00 00 00 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc90001c879c0 EFLAGS: 00000287
RAX: 1ffff110236f3874 RBX: ffffffffffffff28 RCX: dffffc0000000000
RDX: ffffc9000f6c9000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90001c87a10 R08: ffff88814ca6866f R09: 0000000000000000
R10: ffff88814ca68660 R11: ffffed102994d0ce R12: ffff88811b79c380
R13: ffff88815aca7ee0 R14: ffff88811b79c3a0 R15: ffff8881103d3c00
FS: 00007f19df7f76c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000012d830000 CR4: 00000000003526b0
Call Trace:
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: 0033:0x7f19e0d8eec9
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:00007f19df7f7038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f19e0fe5fa0 RCX: 00007f19e0d8eec9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000380
RBP: 00007f19e0e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002125099 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19e0fe6038 R14: 00007f19e0fe5fa0 R15: 00007ffdddb6c478