From: Dmitry Osipenko Date: Sun, 8 Jan 2023 21:13:11 +0000 (+0300) Subject: drm/shmem-helper: Remove another errant put in error path X-Git-Tag: v6.1.21~47 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dede8c14a37a7ac458f9add56154a074ed78e7cf;p=platform%2Fkernel%2Flinux-starfive.git drm/shmem-helper: Remove another errant put in error path commit ee9adb7a45516cfa536ca92253d7ae59d56db9e4 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 7af9da886d4e..5fdc608043e7 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);