omap_gem_new_dmabuf() creates the new gem object, and then takes and
holds the omap_obj->lock for the rest of the function. This has two
issues:
- omap_gem_free_object(), which is called in the error paths, also takes
the same lock, leading to deadlock
- Even if the above wouldn't happen, in the error cases
omap_gem_new_dmabuf() still unlocks omap_obj->lock, even after the
omap_obj has already been freed.
Furthermore, I don't think there's any reason to take the lock at all,
as the object was just created and not yet shared with anyone else.
To fix all this, drop taking the lock.
Fixes: 3cbd0c587b12 ("drm/omap: gem: Replace struct_mutex usage with omap_obj private lock")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/511b99d7-aade-4f92-bd3e-63163a13d617@stanley.mountain/
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/omapdrm/omap_gem.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
index 9ea0c64c26b5..ebbe80c1c0ef 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem.c
@@ -1402,8 +1402,6 @@ struct drm_gem_object *omap_gem_new_dmabuf(struct drm_device *dev, size_t size,
omap_obj = to_omap_bo(obj);
- mutex_lock(&omap_obj->lock);
-
omap_obj->sgt = sgt;
if (omap_gem_sgt_is_contiguous(sgt, size)) {
@@ -1418,21 +1416,17 @@ struct drm_gem_object *omap_gem_new_dmabuf(struct drm_device *dev, size_t size,
pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL);
if (!pages) {
omap_gem_free_object(obj);
- obj = ERR_PTR(-ENOMEM);
- goto done;
+ return ERR_PTR(-ENOMEM);
}
omap_obj->pages = pages;
ret = drm_prime_sg_to_page_array(sgt, pages, npages);
if (ret) {
omap_gem_free_object(obj);
- obj = ERR_PTR(-ENOMEM);
- goto done;
+ return ERR_PTR(-ENOMEM);
}
}
-done:
- mutex_unlock(&omap_obj->lock);
return obj;
}
--
2.43.0
