From b9770b0b6eac2be3772b6f4748e6b899a9ab2870 Mon Sep 17 00:00:00 2001 From: Pavel Skripkin Date: Wed, 11 Aug 2021 20:50:52 +0300 Subject: [PATCH] udmabuf: fix general protection fault in udmabuf_create 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 Link: http://patchwork.freedesktop.org/patch/msgid/20210811175052.21254-1-paskripkin@gmail.com Signed-off-by: Gerd Hoffmann --- drivers/dma-buf/udmabuf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 8df761a102511..c57a609db75be 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -227,8 +227,8 @@ static long udmabuf_create(struct miscdevice *device, if (!hpage) { hpage = find_get_page_flags(mapping, pgoff, FGP_ACCESSED); - if (IS_ERR(hpage)) { - ret = PTR_ERR(hpage); + if (!hpage) { + ret = -EINVAL; goto err; } } -- 2.39.5