6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tomi Valkeinen tomi.valkeinen@ideasonboard.com
[ Upstream commit e6a1c4037227539373c8cf484ace83833e2ad6a2 ]
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@linaro.org Closes: https://lore.kernel.org/all/511b99d7-aade-4f92-bd3e-63163a13d617@stanley.mou... Reviewed-by: Sebastian Reichel sebastian.reichel@collabora.com Signed-off-by: Tomi Valkeinen tomi.valkeinen@ideasonboard.com Link: https://patchwork.freedesktop.org/patch/msgid/20240806-omapdrm-misc-fixes-v1... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 c48fa531ca321..68117eed702be 100644 --- a/drivers/gpu/drm/omapdrm/omap_gem.c +++ b/drivers/gpu/drm/omapdrm/omap_gem.c @@ -1395,8 +1395,6 @@ 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 (sgt->orig_nents == 1) { @@ -1411,21 +1409,17 @@ 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; }