Patch "tcp: fix tcp_fastopen unaligned access complaints on sparc" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

tcp: fix tcp_fastopen unaligned access complaints on sparc

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tcp-fix-tcp_fastopen-unaligned-access-complaints-on-sparc.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Shannon Nelson <[email protected]>
Date: Thu, 12 Jan 2017 14:24:58 -0800
Subject: tcp: fix tcp_fastopen unaligned access complaints on sparc

From: Shannon Nelson <[email protected]>

[ Upstream commit 003c941057eaa868ca6fedd29a274c863167230d ]

Fix up a data alignment issue on sparc by swapping the order of the cookie byte array field with the length field in struct tcp_fastopen_cookie, and making it a proper union to clean up the typecasting.

This addresses log complaints like these:

    log_unaligned: 113 callbacks suppressed
    Kernel unaligned access at TPC[976490] tcp_try_fastopen+0x2d0/0x360
    Kernel unaligned access at TPC[9764ac] tcp_try_fastopen+0x2ec/0x360
    Kernel unaligned access at TPC[9764c8] tcp_try_fastopen+0x308/0x360
    Kernel unaligned access at TPC[9764e4] tcp_try_fastopen+0x324/0x360
    Kernel unaligned access at TPC[976490] tcp_try_fastopen+0x2d0/0x360

---
 include/linux/tcp.h     |    7 ++++++-
 net/ipv4/tcp_fastopen.c |    2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

@@ -62,8 +62,13 @@ static inline unsigned int tcp_optlen(co
 
 /* TCP Fast Open Cookie as stored in memory */
 struct tcp_fastopen_cookie {
+	union {
+		u8	val[TCP_FASTOPEN_COOKIE_MAX];
+#if IS_ENABLED(CONFIG_IPV6)
+		struct in6_addr addr;
+#endif
+	};
 	s8	len;
-	u8	val[TCP_FASTOPEN_COOKIE_MAX];
 	bool	exp;	/* In RFC6994 experimental option format */
 };
 

@@ -113,7 +113,7 @@ static bool tcp_fastopen_cookie_gen(stru
 		struct tcp_fastopen_cookie tmp;
 
 		if (__tcp_fastopen_cookie_gen(&ip6h->saddr, &tmp)) {
-			struct in6_addr *buf = (struct in6_addr *) tmp.val;
+			struct in6_addr *buf = &tmp.addr;
 			int i;
 
 			for (i = 0; i < 4; i++)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/tcp-fix-tcp_fastopen-unaligned-access-complaints-on-sparc.patch