From: Dmitry Osipenko Date: Sun, 30 Oct 2022 15:44:12 +0000 (+0300) Subject: drm/client: Prevent NULL dereference in drm_client_buffer_delete() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=444bbba708e804c13ad757068d1cb31ed6460754;p=linux.git drm/client: Prevent NULL dereference in drm_client_buffer_delete() The drm_gem_vunmap() will crash with a NULL dereference if the passed object pointer is NULL. It wasn't a problem before we added the locking support to drm_gem_vunmap function because the mapping argument was always NULL together with the object. Make drm_client_buffer_delete() to check whether GEM is NULL before trying to unmap the GEM, it will happen on framebuffer creation error. Reported-by: Dan Carpenter Reviewed-by: Christian König Link: https://lore.kernel.org/dri-devel/Y1kFEGxT8MVlf32V@kili/ Fixes: 79e2cf2e7a19 ("drm/gem: Take reservation lock for vmap/vunmap operations") Signed-off-by: Dmitry Osipenko Link: https://patchwork.freedesktop.org/patch/msgid/20221030154412.8320-3-dmitry.osipenko@collabora.com --- diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index 38e1be991caa5..fd67efe37c636 100644 --- a/drivers/gpu/drm/drm_client.c +++ b/drivers/gpu/drm/drm_client.c @@ -235,10 +235,10 @@ static void drm_client_buffer_delete(struct drm_client_buffer *buffer) { struct drm_device *dev = buffer->client->dev; - drm_gem_vunmap_unlocked(buffer->gem, &buffer->map); - - if (buffer->gem) + if (buffer->gem) { + drm_gem_vunmap_unlocked(buffer->gem, &buffer->map); drm_gem_object_put(buffer->gem); + } if (buffer->handle) drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);