Re: [Linaro-mm-sig] [PATCH next] udmabuf: fix general protection fault in udmabuf_create

On Wed, Aug 11, 2021 at 08:50:52PM +0300, Pavel Skripkin wrote:

Syzbot reported general protection fault in udmabuf_create. The problem was in wrong error handling.

In commit 16c243e99d33 ("udmabuf: Add support for mapping hugepages (v4)") shmem_read_mapping_page() call was replaced with find_get_page_flags(), but find_get_page_flags() returns NULL on failure instead PTR_ERR().

Wrong error checking was causing GPF in get_page(), since passed page was equal to NULL. Fix it by changing if (IS_ER(!hpage)) to if (!hpage)

Reported-by: syzbot+e9cd3122a37c5d6c51e8@syzkaller.appspotmail.com Fixes: 16c243e99d33 ("udmabuf: Add support for mapping hugepages (v4)") Signed-off-by: Pavel Skripkin paskripkin@gmail.com

Pushed to drm-misc-next.

thanks, Gerd