[030/126] block: avoid using uninitialized value in from queue_var_store

Steven Rostedt
2013-05-07T04:06:50Z

[-- Attachment #1: 0030-block-avoid-using-uninitialized-value-in-from-queue_.patch --]
[-- Type: text/plain, Size: 1360 bytes --]

3.6.11.3 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit c678ef5286ddb5cf70384ad5af286b0afc9b73e1 ]

As found by gcc-4.8, the QUEUE_SYSFS_BIT_FNS macro creates functions
that use a value generated by queue_var_store independent of whether
that value was set or not.

block/blk-sysfs.c: In function 'queue_store_nonrot':
block/blk-sysfs.c:244:385: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]

Unlike most other such warnings, this one is not a false positive,
writing any non-number string into the sysfs files indeed has
an undefined result, rather than returning an error.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
block/blk-sysfs.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 9628b29..59e77ef 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -207,6 +207,8 @@ queue_store_##name(struct request_queue *q, const char *page, size_t count) \
unsigned long val; \
ssize_t ret; \
ret = queue_var_store(&val, page, count); \
+ if (ret < 0) \
+ return ret; \
if (neg) \
val = !val; \
\
--
1.7.10.4