From: Jike Song Date: Fri, 16 Dec 2016 02:51:04 +0000 (+0800) Subject: drm/i915/gvt/kvmgt: dereference the pointer within lock X-Git-Tag: v4.10-rc3~19^2~8^2~5 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bfeca3e5716a16b95a1fb7104e477ca3bd5ed59e;p=karo-tx-linux.git 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 --- 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 @@ out: 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)