From bfeca3e5716a16b95a1fb7104e477ca3bd5ed59e Mon Sep 17 00:00:00 2001 From: Jike Song Date: Fri, 16 Dec 2016 10:51:04 +0800 Subject: [PATCH] drm/i915/gvt/kvmgt: dereference the pointer within lock Though there is no issue exposed yet, it's possible that another thread releases the entry while our trying to deref it out of the lock. Fit it by moving the dereference within lock. Signed-off-by: Jike Song Signed-off-by: Zhenyu Wang --- drivers/gpu/drm/i915/gvt/kvmgt.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 4dd6722a7339..4ba196796846 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -114,12 +114,15 @@ static struct gvt_dma *__gvt_cache_find(struct intel_vgpu *vgpu, gfn_t gfn) static kvm_pfn_t gvt_cache_find(struct intel_vgpu *vgpu, gfn_t gfn) { struct gvt_dma *entry; + kvm_pfn_t pfn; mutex_lock(&vgpu->vdev.cache_lock); + entry = __gvt_cache_find(vgpu, gfn); - mutex_unlock(&vgpu->vdev.cache_lock); + pfn = (entry == NULL) ? 0 : entry->pfn; - return entry == NULL ? 0 : entry->pfn; + mutex_unlock(&vgpu->vdev.cache_lock); + return pfn; } static void gvt_cache_add(struct intel_vgpu *vgpu, gfn_t gfn, kvm_pfn_t pfn) -- 2.45.2