2020-03-16 07:00:32

by Qiujun Huang

Subject: [PATCH] drm/lease: fix potential race in fill_object_idr

We should hold idr_mutex for idr_alloc.

Signed-off-by: Qiujun Huang <[email protected]>
---
drivers/gpu/drm/drm_lease.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
index b481caf..427ee21 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -418,6 +418,7 @@ static int fill_object_idr(struct drm_device *dev,
goto out_free_objects;
}

+ mutex_lock(&dev->mode_config.idr_mutex);
/* add their IDs to the lease request - taking into account
universal planes */
for (o = 0; o < object_count; o++) {
@@ -437,7 +438,7 @@ static int fill_object_idr(struct drm_device *dev,
if (ret < 0) {
DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
object_id, ret);
- goto out_free_objects;
+ goto out_unlock;
}
if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {
struct drm_crtc *crtc = obj_to_crtc(obj);
@@ -445,20 +446,22 @@ static int fill_object_idr(struct drm_device *dev,
if (ret < 0) {
DRM_DEBUG_LEASE("Object primary plane %d cannot be inserted into leases (%d)\n",
object_id, ret);
- goto out_free_objects;
+ goto out_unlock;
}
if (crtc->cursor) {
ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);
if (ret < 0) {
DRM_DEBUG_LEASE("Object cursor plane %d cannot be inserted into leases (%d)\n",
object_id, ret);
- goto out_free_objects;
+ goto out_unlock;
}
}
}
}

ret = 0;
+out_unlock:
+ mutex_unlock(&dev->mode_config.idr_mutex);
out_free_objects:
for (o = 0; o < object_count; o++) {
if (objects[o])
--
1.8.3.1

2020-03-16 07:16:35

by Qiujun Huang

Subject: Re: [PATCH] drm/lease: fix potential race in fill_object_idr

Sorry about sending to wrong maintainers. Please ignore it.
I'll resend it.

On Mon, Mar 16, 2020 at 2:59 PM Qiujun Huang <[email protected]> wrote:
>
> We should hold idr_mutex for idr_alloc.
>
> Signed-off-by: Qiujun Huang <[email protected]>
> ---
> drivers/gpu/drm/drm_lease.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
> index b481caf..427ee21 100644
> --- a/drivers/gpu/drm/drm_lease.c
> +++ b/drivers/gpu/drm/drm_lease.c
> @@ -418,6 +418,7 @@ static int fill_object_idr(struct drm_device *dev,
> goto out_free_objects;
> }
>
> + mutex_lock(&dev->mode_config.idr_mutex);
> /* add their IDs to the lease request - taking into account
> universal planes */
> for (o = 0; o < object_count; o++) {
> @@ -437,7 +438,7 @@ static int fill_object_idr(struct drm_device *dev,
> if (ret < 0) {
> DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
> object_id, ret);
> - goto out_free_objects;
> + goto out_unlock;
> }
> if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {
> struct drm_crtc *crtc = obj_to_crtc(obj);
> @@ -445,20 +446,22 @@ static int fill_object_idr(struct drm_device *dev,
> if (ret < 0) {
> DRM_DEBUG_LEASE("Object primary plane %d cannot be inserted into leases (%d)\n",
> object_id, ret);
> - goto out_free_objects;
> + goto out_unlock;
> }
> if (crtc->cursor) {
> ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);
> if (ret < 0) {
> DRM_DEBUG_LEASE("Object cursor plane %d cannot be inserted into leases (%d)\n",
> object_id, ret);
> - goto out_free_objects;
> + goto out_unlock;
> }
> }
> }
> }
>
> ret = 0;
> +out_unlock:
> + mutex_unlock(&dev->mode_config.idr_mutex);
> out_free_objects:
> for (o = 0; o < object_count; o++) {
> if (objects[o])
> --
> 1.8.3.1
>