linux-kernel - [PATCH] rpc: fix garbage in printk in svc_tcp

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Message-ID: <20070920195146.GC23287@fieldses.org>
Date:	Thu, 20 Sep 2007 15:51:46 -0400
From:	"J. Bruce Fields" <bfields@...ldses.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Wolfgang Walter <wolfgang.walter@...dentenwerk.mhn.de>,
	Neil Brown <neilb@...e.de>, Trond Myklebust <trond@...app.com>,
	stable@...nel.org
Subject: [PATCH] rpc: fix garbage in printk in svc_tcp_accept()

we upgraded the kernel of a nfs-server from 2.6.17.11 to 2.6.22.6. Since
then we get the message

lockd: too many open TCP sockets, consider increasing the number of nfsd threads
lockd: last TCP connect from ^\\236^\É^D

These random characters in the second line are caused by a bug in
svc_tcp_accept.

(Note: there are two previous __svc_print_addr(sin, buf, sizeof(buf))
calls in this function, either of which would initialize buf correctly;
but both are inside "if"'s and are not necessarily executed.  This is
less obvious in the second case, which is inside a dprintk(), which is a
macro which expands to an if statement.)

Signed-off-by: Wolfgang Walter <wolfgang.walter@...dentenwerk.mhn.de>
Signed-off-by: J. Bruce Fields <bfields@...i.umich.edu>
---
 net/sunrpc/svcsock.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

We're printk'ing random uninitialized memory here, which I assume makes
it appropriate for both 2.6.23 and 2.6.22.x.--b.

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 1a89992..036ab52 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1110,7 +1110,8 @@ svc_tcp_accept(struct svc_sock *svsk)
 						   serv->sv_name);
 				printk(KERN_NOTICE
 				       "%s: last TCP connect from %s\n",
-				       serv->sv_name, buf);
+				       serv->sv_name, __svc_print_addr(sin,
+							buf, sizeof(buf)));
 			}
 			/*
 			 * Always select the oldest socket. It's not fair,
-- 
1.5.3.1.139.g9346b

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