From ee9adb7a45516cfa536ca92253d7ae59d56db9e4 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Mon, 9 Jan 2023 00:13:11 +0300 Subject: [PATCH] drm/shmem-helper: Remove another errant put in error path drm_gem_shmem_mmap() doesn't own reference in error code path, resulting in the dma-buf shmem GEM object getting prematurely freed leading to a later use-after-free. Fixes: f49a51bfdc8e ("drm/shme-helpers: Fix dma_buf_mmap forwarding bug") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Osipenko Reviewed-by: Rob Clark Link: https://patchwork.freedesktop.org/patch/msgid/20230108211311.3950107-1-dmitry.osipenko@collabora.com --- drivers/gpu/drm/drm_gem_shmem_helper.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index b602cd72a120..1a681de9a6ea 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -622,11 +622,14 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct int ret; if (obj->import_attach) { - /* Drop the reference drm_gem_mmap_obj() acquired.*/ - drm_gem_object_put(obj); vma->vm_private_data = NULL; + ret = dma_buf_mmap(obj->dma_buf, vma, 0); + + /* Drop the reference drm_gem_mmap_obj() acquired.*/ + if (!ret) + drm_gem_object_put(obj); - return dma_buf_mmap(obj->dma_buf, vma, 0); + return ret; } ret = drm_gem_shmem_get_pages(shmem); -- 2.39.5