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authorWanpeng Li <wanpengli@tencent.com>2019-05-17 16:49:49 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2019-05-24 21:27:03 +0200
commit2eb06c306a579853346d22eda73332ed4f3e81e3 (patch)
treeeb01482c0feab55622cdfcb620563344e9f7c9ca
parent21be4ca1ea685ab3ccc2fd18babb89bc477a9e5c (diff)
downloadlinux-stericsson-2eb06c306a579853346d22eda73332ed4f3e81e3.tar.gz
KVM: Fix spinlock taken warning during host resume
WARNING: CPU: 0 PID: 13554 at kvm/arch/x86/kvm//../../../virt/kvm/kvm_main.c:4183 kvm_resume+0x3c/0x40 [kvm] CPU: 0 PID: 13554 Comm: step_after_susp Tainted: G OE 5.1.0-rc4+ #1 RIP: 0010:kvm_resume+0x3c/0x40 [kvm] Call Trace: syscore_resume+0x63/0x2d0 suspend_devices_and_enter+0x9d1/0xa40 pm_suspend+0x33a/0x3b0 state_store+0x82/0xf0 kobj_attr_store+0x12/0x20 sysfs_kf_write+0x4b/0x60 kernfs_fop_write+0x120/0x1a0 __vfs_write+0x1b/0x40 vfs_write+0xcd/0x1d0 ksys_write+0x5f/0xe0 __x64_sys_write+0x1a/0x20 do_syscall_64+0x6f/0x6c0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Commit ca84d1a24 (KVM: x86: Add clock sync request to hardware enable) mentioned that "we always hold kvm_lock when hardware_enable is called. The one place that doesn't need to worry about it is resume, as resuming a frozen CPU, the spinlock won't be taken." However, commit 6706dae9 (virt/kvm: Replace spin_is_locked() with lockdep) introduces a bug, it asserts when the lock is not held which is contrary to the original goal. This patch fixes it by WARN_ON when the lock is held. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Paul E. McKenney <paulmck@linux.ibm.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Fixes: 6706dae9 ("virt/kvm: Replace spin_is_locked() with lockdep") [Wrap with #ifdef CONFIG_LOCKDEP - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--virt/kvm/kvm_main.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f0d13d9d125d..1fadfb9cf36e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -52,6 +52,7 @@
#include <linux/sort.h>
#include <linux/bsearch.h>
#include <linux/io.h>
+#include <linux/lockdep.h>
#include <asm/processor.h>
#include <asm/ioctl.h>
@@ -4181,7 +4182,9 @@ static int kvm_suspend(void)
static void kvm_resume(void)
{
if (kvm_usage_count) {
- lockdep_assert_held(&kvm_count_lock);
+#ifdef CONFIG_LOCKDEP
+ WARN_ON(lockdep_is_held(&kvm_count_lock));
+#endif
hardware_enable_nolock(NULL);
}
}