[PATCH AUTOSEL 5.15 05/23] KVM: Fix lockdep false negative during host resume

Sasha Levin
2022-03-01T20:19:57Z

From: Wanpeng Li <wanpengli@tencent.com>

[ Upstream commit 4cb9a998b1ce25fad74a82f5a5c45a4ef40de337 ]

I saw the below splatting after the host suspended and resumed.

WARNING: CPU: 0 PID: 2943 at kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:5531 kvm_resume+0x2c/0x30 [kvm]
CPU: 0 PID: 2943 Comm: step_after_susp Tainted: G W IOE 5.17.0-rc3+ #4
RIP: 0010:kvm_resume+0x2c/0x30 [kvm]
Call Trace:
<TASK>
syscore_resume+0x90/0x340
suspend_devices_and_enter+0xaee/0xe90
pm_suspend.cold+0x36b/0x3c2
state_store+0x82/0xf0
kernfs_fop_write_iter+0x1b6/0x260
new_sync_write+0x258/0x370
vfs_write+0x33f/0x510
ksys_write+0xc9/0x160
do_syscall_64+0x3b/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae

lockdep_is_held() can return -1 when lockdep is disabled which triggers
this warning. Let's use lockdep_assert_not_held() which can detect
incorrect calls while holding a lock and it also avoids false negatives
when lockdep is disabled.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1644920142-81249-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
virt/kvm/kvm_main.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 13aff136e6eef..5309b3eaa0470 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5416,9 +5416,7 @@ static int kvm_suspend(void)
static void kvm_resume(void)
{
if (kvm_usage_count) {
-#ifdef CONFIG_LOCKDEP
- WARN_ON(lockdep_is_held(&kvm_count_lock));
-#endif
+ lockdep_assert_not_held(&kvm_count_lock);
hardware_enable_nolock(NULL);
}
}
--
2.34.1