From: Colin Ian King colin.king@canonical.com
info is being checked to see if it is a null pointer, however, vpgu is dereferencing info before this check, leading to a potential null pointer dereference. If info is null, then the error message being printed by macro gvt_vgpu_err and this requires vpgu to exist. We can use a null vpgu as the macro has a sanity check to see if vpgu is null, so this is OK.
Detected with CoverityScan, CID#1420672 ("Dereference nefore null check")
Fixes: 695fbc08d80f ("drm/i915/gvt: replace the gvt_err with gvt_vgpu_err") Signed-off-by: Colin Ian King colin.king@canonical.com --- drivers/gpu/drm/i915/gvt/kvmgt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 1ea3eb270de8..f8619a772c44 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -1339,9 +1339,9 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
static bool kvmgt_guest_exit(struct kvmgt_guest_info *info) { - struct intel_vgpu *vgpu = info->vgpu; - if (!info) { + struct intel_vgpu *vgpu = NULL; + gvt_vgpu_err("kvmgt_guest_info invalid\n"); return false; }
On Thu, Mar 23, 2017 at 12:22:30PM +0000, Colin King wrote:
From: Colin Ian King colin.king@canonical.com
info is being checked to see if it is a null pointer, however, vpgu is dereferencing info before this check, leading to a potential null pointer dereference. If info is null, then the error message being printed by macro gvt_vgpu_err and this requires vpgu to exist. We can use a null vpgu as the macro has a sanity check to see if vpgu is null, so this is OK.
It is never NULL, it gets checked by its only caller. -Chris
On Thu, Mar 23, 2017 at 1:22 PM, Colin King colin.king@canonical.com wrote:
From: Colin Ian King colin.king@canonical.com
info is being checked to see if it is a null pointer, however, vpgu is dereferencing info before this check, leading to a potential null pointer dereference. If info is null, then the error message being printed by macro gvt_vgpu_err and this requires vpgu to exist. We can use a null vpgu as the macro has a sanity check to see if vpgu is null, so this is OK.
Detected with CoverityScan, CID#1420672 ("Dereference nefore null check")
s,nefore,before,
Fixes: 695fbc08d80f ("drm/i915/gvt: replace the gvt_err with gvt_vgpu_err") Signed-off-by: Colin Ian King colin.king@canonical.com
drivers/gpu/drm/i915/gvt/kvmgt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 1ea3eb270de8..f8619a772c44 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -1339,9 +1339,9 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
static bool kvmgt_guest_exit(struct kvmgt_guest_info *info) {
struct intel_vgpu *vgpu = info->vgpu;if (!info) {
struct intel_vgpu *vgpu = NULL;gvt_vgpu_err("kvmgt_guest_info invalid\n"); return false; }
Does this mean the original gvt_err() macro is no longer there?
And apparently gvt_vgpu_err is a macro that depends on the specifics of its environment? Yikes.
Cheers, Frans
On 2017.03.23 14:43:44 +0100, Frans Klaver wrote:
On Thu, Mar 23, 2017 at 1:22 PM, Colin King colin.king@canonical.com wrote:
From: Colin Ian King colin.king@canonical.com
info is being checked to see if it is a null pointer, however, vpgu is dereferencing info before this check, leading to a potential null pointer dereference. If info is null, then the error message being printed by macro gvt_vgpu_err and this requires vpgu to exist. We can use a null vpgu as the macro has a sanity check to see if vpgu is null, so this is OK.
Detected with CoverityScan, CID#1420672 ("Dereference nefore null check")
s,nefore,before,
Fixes: 695fbc08d80f ("drm/i915/gvt: replace the gvt_err with gvt_vgpu_err") Signed-off-by: Colin Ian King colin.king@canonical.com
drivers/gpu/drm/i915/gvt/kvmgt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 1ea3eb270de8..f8619a772c44 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -1339,9 +1339,9 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
static bool kvmgt_guest_exit(struct kvmgt_guest_info *info) {
struct intel_vgpu *vgpu = info->vgpu;if (!info) {
struct intel_vgpu *vgpu = NULL;gvt_vgpu_err("kvmgt_guest_info invalid\n"); return false; }Does this mean the original gvt_err() macro is no longer there?
And apparently gvt_vgpu_err is a macro that depends on the specifics of its environment? Yikes.
The null check is redundant there, we can just remove that block and extra vgpu variable.
dri-devel@lists.freedesktop.org
-
Chris Wilson -
Colin King -
Frans Klaver -
Zhenyu Wang