linux-kernel - [PATCH] misc: sgi-xp: Properly initialize buf in xpc_get_rsvd_page

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Date:   Thu, 23 May 2019 09:15:33 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Cliff Whickman <cpw@....com>, Robin Holt <robinmholt@...il.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Stephen Hines <srhines@...gle.com>
Subject: [PATCH] misc: sgi-xp: Properly initialize buf in xpc_get_rsvd_page_pa

Clang warns:

drivers/misc/sgi-xp/xpc_partition.c:73:14: warning: variable 'buf' is
uninitialized when used within its own initialization [-Wuninitialized]
        void *buf = buf;
              ~~~   ^~~
1 warning generated.

Initialize it to NULL, which is more deterministic.

Fixes: 279290294662 ("[IA64-SGI] cleanup the way XPC locates the reserved page")
Link: https://github.com/ClangBuiltLinux/linux/issues/466
Suggested-by: Stephen Hines <srhines@...gle.com>
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---

Thanks Steve for the suggestion, don't know why that never crossed my
mind...

I tried to follow buf all the way down in get_partition_rsvd_page to see
if there would be any dereferences and I didn't see any but I could
have easily missed something.

 drivers/misc/sgi-xp/xpc_partition.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/sgi-xp/xpc_partition.c b/drivers/misc/sgi-xp/xpc_partition.c
index 3eba1c420cc0..782ce95d3f17 100644
--- a/drivers/misc/sgi-xp/xpc_partition.c
+++ b/drivers/misc/sgi-xp/xpc_partition.c
@@ -70,7 +70,7 @@ xpc_get_rsvd_page_pa(int nasid)
 	unsigned long rp_pa = nasid;	/* seed with nasid */
 	size_t len = 0;
 	size_t buf_len = 0;
-	void *buf = buf;
+	void *buf = NULL;
 	void *buf_base = NULL;
 	enum xp_retval (*get_partition_rsvd_page_pa)
 		(void *, u64 *, unsigned long *, size_t *) =
-- 
2.22.0.rc1