watchdog: BUG: soft lockup - CPU#1 stuck for 143s! [syz.0.2974:7069]
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: 7069 Comm: syz.0.2974 Not tainted syzkaller #0 24a10c3d70c948d82bad81e39d295aea70670ee6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__lookup_mnt+0xb4/0x160 fs/namespace.c:815
Code: 02 89 ec ff 4d 8b 3f 4d 85 ff 74 7f 4d 8d 67 10 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 e0 88 ec ff 49 8b 04 24 <48> 83 c0 20 4c 39 f0 74 07 e8 7e bd 94 ff eb 25 4d 8d 67 18 4c 89
RSP: 0018:ffffc900011afae8 EFLAGS: 00000246
RAX: ffff88814c0acc40 RBX: ffff888113c16660 RCX: 0000000000080000
RDX: ffffc90007277000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900011afb10 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000235f9c R12: ffff88814c0ada50
R13: dffffc0000000000 R14: ffff8881086cae20 R15: ffff88814c0ada40
FS: 00007f95a5e006c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000008000 CR3: 000000012dc74000 CR4: 00000000003526b0
Call Trace:
propagate_umount+0x5a8/0x1690 fs/pnode.c:597
umount_tree+0x604/0xf90 fs/namespace.c:1786
do_umount fs/namespace.c:-1 [inline]
path_umount+0xeb3/0xf50 fs/namespace.c:2020
ksys_umount fs/namespace.c:2043 [inline]
__do_sys_umount fs/namespace.c:2048 [inline]
__se_sys_umount fs/namespace.c:2046 [inline]
__x64_sys_umount+0x12e/0x180 fs/namespace.c:2046
x64_sys_call+0x2ab8/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:167
do_syscall_x64 arch/x86/entry/common.c:47 [inline]
do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f95a4f9bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f95a5e00028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f95a5216360 RCX: 00007f95a4f9bf79
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000200000000040
RBP: 00007f95a50327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f95a52163f8 R14: 00007f95a5216360 R15: 00007ffc5aa5a1e8
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7044 Comm: syz.3.2967 Not tainted syzkaller #0 24a10c3d70c948d82bad81e39d295aea70670ee6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc cc cc cc cc b8 3b 63 f3 91 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 8c 48 00 55 48 89 e5 fb f4 <5d> c3 cc cc cc cc cc cc cc cc cc cc cc b8 00 00 00 00 90 90 90 90
RSP: 0018:ffffc9000fb77850 EFLAGS: 00000246
RAX: ffffffff814428e1 RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc9000466d000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000fb77850 R08: ffffffff8740d604 R09: 1ffffffff0e81ac0
R10: dffffc0000000000 R11: fffffbfff0e81ac1 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92001f6ef0c
FS: 00007fed3fe276c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8cf5de96c0 CR3: 000000011e67c000 CR4: 00000000003526b0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline]
kvm_wait+0x1c6/0x230 arch/x86/kernel/kvm.c:1081
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+0x8e0/0xe90 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+0x115/0x120 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:225 [inline]
mntput_no_expire+0x157/0x6d0 fs/namespace.c:1421
mntput fs/namespace.c:1476 [inline]
cleanup_mnt+0x327/0x4a0 fs/namespace.c:1376
__cleanup_mnt+0x1d/0x40 fs/namespace.c:1387
task_work_run+0x1e5/0x260 kernel/task_work.c:246
get_signal+0x1302/0x14e0 kernel/signal.c:2706
arch_do_signal_or_restart+0xbc/0x760 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x57/0xb0 kernel/entry/common.c:218
do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fed3ef9bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed3fe26fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: fffffffffffffffc RBX: 00007fed3f216180 RCX: 00007fed3ef9bf79
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000b21e0000
RBP: 00007fed3f0327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fed3f216218 R14: 00007fed3f216180 R15: 00007fffe2afcc08