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authorKeith Packard <keithp@keithp.com>2017-12-20 22:54:24 -0800
committerDaniel Vetter <daniel.vetter@ffwll.ch>2017-12-21 09:49:40 +0100
commitd2a48e52541cdf474ef35d51e8d73ded5be33122 (patch)
tree9a722b300870bd111d323e2131dd0aca6715d851
parentdrm/plane: Make framebuffer refcounting the responsibility of setplane_internal callers (diff)
downloadlinux-dev-d2a48e52541cdf474ef35d51e8d73ded5be33122.tar.xz
linux-dev-d2a48e52541cdf474ef35d51e8d73ded5be33122.zip
drm: move lease init after validation in drm_lease_create
Patch bd36d3bab2e3d08f80766c86487090dbceed4651 fixed a deadlock in the failure path of drm_lease_create. This made the partially initialized lease object visible for a short window of time. To avoid having the lessee state appear transiently, I've rearranged the code so that the lessor fields are not filled in until the parameters are all validated and the function will succeed. Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20171221065424.1304-1-keithp@keithp.com
-rw-r--r--drivers/gpu/drm/drm_lease.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
index 59849f02e2ad..1402c0e71b03 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -220,17 +220,6 @@ static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr
mutex_lock(&dev->mode_config.idr_mutex);
- /* Insert the new lessee into the tree */
- id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL);
- if (id < 0) {
- error = id;
- goto out_lessee;
- }
-
- lessee->lessee_id = id;
- lessee->lessor = drm_master_get(lessor);
- list_add_tail(&lessee->lessee_list, &lessor->lessees);
-
idr_for_each_entry(leases, entry, object) {
error = 0;
if (!idr_find(&dev->mode_config.crtc_idr, object))
@@ -246,6 +235,17 @@ static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr
}
}
+ /* Insert the new lessee into the tree */
+ id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL);
+ if (id < 0) {
+ error = id;
+ goto out_lessee;
+ }
+
+ lessee->lessee_id = id;
+ lessee->lessor = drm_master_get(lessor);
+ list_add_tail(&lessee->lessee_list, &lessor->lessees);
+
/* Move the leases over */
lessee->leases = *leases;
DRM_DEBUG_LEASE("new lessee %d %p, lessor %d %p\n", lessee->lessee_id, lessee, lessor->lessee_id, lessor);