This is a note to let you know that I've just added the patch titled
misc: genwqe: check for error from get_user_pages_fast()
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From cf35d6e0475982667b0d2d318fb27be4b8849827 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Thu, 6 Nov 2014 16:23:39 +0000
Subject: misc: genwqe: check for error from get_user_pages_fast()
`genwqe_user_vmap()` calls `get_user_pages_fast()` and if the return
value is less than the number of pages requested, it frees the pages and
returns an error (`-EFAULT`). However, it fails to consider a negative
error return value from `get_user_pages_fast()`. In that case, the test
`if (rc < m->nr_pages)` will be false (due to promotion of `rc` to a
large `unsigned int`) and the code will continue on to call
`genwqe_map_pages()` with an invalid list of page pointers. Fix it by
bailing out if `get_user_pages_fast()` returns a negative error value.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 3.14.x # 3.15.x # 3.16.x # 3.17.x
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/misc/genwqe/card_utils.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
index 7cb3b7e41739..1ca94e6fa8fb 100644
--- a/drivers/misc/genwqe/card_utils.c
+++ b/drivers/misc/genwqe/card_utils.c
@@ -590,6 +590,8 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr,
m->nr_pages,
1, /* write by caller */
m->page_list); /* ptrs to pages */
+ if (rc < 0)
+ goto fail_get_user_pages;
/* assumption: get_user_pages can be killed by signals. */
if (rc < m->nr_pages) {
--
2.1.3
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