watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.1.10967:26258]
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, 0% softirq, 1% hardirq, 0% idle
#5: 100% system, 1% softirq, 1% hardirq, 0% idle
Modules linked in:
CPU: 0 UID: 0 PID: 26258 Comm: syz.1.10967 Not tainted syzkaller #0 ab9e215a8d79cd87c3adea34e0b2794648952c95
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0x17/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc b8 35 df 86 ac 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 02 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:ffffc9000762fa10 EFLAGS: 000002d3
RAX: ffffffff81439535 RBX: 0000000000000003 RCX: ffff8881446e0000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: ffffc9000762fa10 R08: ffffffff8720d604 R09: 1ffffffff0e41ac0
R10: dffffc0000000000 R11: fffffbfff0e41ac1 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000ec5f44
FS: 0000555587199500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f11aff8 CR3: 0000000117924000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000002009800
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
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
__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: 0033:0x7fe512f8efc9
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:00007fff8c340838 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fe5131e7da0 RCX: 00007fe512f8efc9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fe5131e7da0 R08: 000000000000019c R09: 000000178c340b2f
R10: 00007fe5131e7cb0 R11: 0000000000000246 R12: 00000000000761f0
R13: 00007fe5131e6090 R14: ffffffffffffffff R15: 00007fff8c340950
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 26239 Comm: syz.2.10961 Not tainted syzkaller #0 ab9e215a8d79cd87c3adea34e0b2794648952c95
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 47 51 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:ffffc900074efa80 EFLAGS: 00000287
RAX: 1ffff1102349e34c RBX: ffffffffffffff28 RCX: dffffc0000000000
RDX: ffffc900021b4000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900074efad0 R08: ffff88811bc24f2f R09: 0000000000000000
R10: ffff88811bc24f20 R11: ffffed10237849e6 R12: ffff88811a4f1a40
R13: ffff8881155eccc0 R14: ffff88811a4f1a60 R15: ffff88813d6e1dc0
FS: 00007f65f82c76c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000013fd56000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<TASK>
umount_tree+0xdfd/0xf70 fs/namespace.c:1803
attach_recursive_mnt+0x6df/0x21e0 fs/namespace.c:2549
do_move_mount+0x608/0x810 fs/namespace.c:3374
__do_sys_move_mount fs/namespace.c:4308 [inline]
__se_sys_move_mount+0x28b/0xad0 fs/namespace.c:4260
__x64_sys_move_mount+0xc3/0xf0 fs/namespace.c:4260
x64_sys_call+0x2342/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:430
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: 0033:0x7f65f738efc9
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:00007f65f82c7038 EFLAGS: 00000246 ORIG_RAX: 00000000000001ad
RAX: ffffffffffffffda RBX: 00007f65f75e5fa0 RCX: 00007f65f738efc9
RDX: ffffffffffffff9c RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007f65f7411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000180 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f65f75e6038 R14: 00007f65f75e5fa0 R15: 00007ffc1b447898
</TASK>