* [PATCH next] udmabuf: fix general protection fault in udmabuf_create
@ 2021-08-11 17:50 Pavel Skripkin
2021-08-12 7:32 ` Gerd Hoffmann
0 siblings, 1 reply; 2+ messages in thread
From: Pavel Skripkin @ 2021-08-11 17:50 UTC (permalink / raw)
To: kraxel, sumit.semwal, christian.koenig, dongwon.kim
Cc: linux-media, linaro-mm-sig, linux-kernel, Pavel Skripkin,
syzbot+e9cd3122a37c5d6c51e8
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>
---
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 8df761a10251..c57a609db75b 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;
}
}
--
2.32.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH next] udmabuf: fix general protection fault in udmabuf_create
2021-08-11 17:50 [PATCH next] udmabuf: fix general protection fault in udmabuf_create Pavel Skripkin
@ 2021-08-12 7:32 ` Gerd Hoffmann
0 siblings, 0 replies; 2+ messages in thread
From: Gerd Hoffmann @ 2021-08-12 7:32 UTC (permalink / raw)
To: Pavel Skripkin
Cc: sumit.semwal, christian.koenig, dongwon.kim, linux-media,
linaro-mm-sig, linux-kernel, syzbot+e9cd3122a37c5d6c51e8
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
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2021-08-12 7:32 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-11 17:50 [PATCH next] udmabuf: fix general protection fault in udmabuf_create Pavel Skripkin
2021-08-12 7:32 ` Gerd Hoffmann
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).