From 444bbba708e804c13ad757068d1cb31ed6460754 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Sun, 30 Oct 2022 18:44:12 +0300 Subject: [PATCH] drm/client: Prevent NULL dereference in drm_client_buffer_delete() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 --- drivers/gpu/drm/drm_client.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index 38e1be9..fd67efe 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); -- 2.7.4