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| author | Wanpeng Li <wanpengli@tencent.com> | 2019-05-17 16:49:49 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-05-24 21:27:03 +0200 |
| commit | 2eb06c306a579853346d22eda73332ed4f3e81e3 (patch) | |
| tree | eb01482c0feab55622cdfcb620563344e9f7c9ca /virt | |
| parent | 21be4ca1ea685ab3ccc2fd18babb89bc477a9e5c (diff) | |
| download | lwn-2eb06c306a579853346d22eda73332ed4f3e81e3.tar.gz lwn-2eb06c306a579853346d22eda73332ed4f3e81e3.zip | |
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>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 5 |
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); } } |