This is a note to let you know that I've just added the patch titled
udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet
to the 2.6.33-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.33.git;a=summary
The filename of the patch is:
udp-recvmsg-clear-msg_trunc-flag-when-starting-over-for-a-new-packet.patch
and it can be found in the queue-2.6.33 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.33 longterm
tree,
please let <sta...@kernel.org> know about it.
>From c40d1703fad9852603d7a84156168b46ae2abbcf Mon Sep 17 00:00:00 2001
From: Xufeng Zhang <xufeng.zh...@windriver.com>
Date: Tue, 21 Jun 2011 10:43:40 +0000
Subject: udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet
From: Xufeng Zhang <xufeng.zh...@windriver.com>
[ Upstream commit 9cfaa8def1c795a512bc04f2aec333b03724ca2e ]
Consider this scenario: When the size of the first received udp packet
is bigger than the receive buffer, MSG_TRUNC bit is set in msg->msg_flags.
However, if checksum error happens and this is a blocking socket, it will
goto try_again loop to receive the next packet. But if the size of the
next udp packet is smaller than receive buffer, MSG_TRUNC flag should not
be set, but because MSG_TRUNC bit is not cleared in msg->msg_flags before
receive the next packet, MSG_TRUNC is still set, which is wrong.
Fix this problem by clearing MSG_TRUNC flag when starting over for a
new packet.
Signed-off-by: Xufeng Zhang <xufeng.zh...@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@suse.de>
---
net/ipv4/udp.c | 3 +++
net/ipv6/udp.c | 3 +++
2 files changed, 6 insertions(+)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1203,6 +1203,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -443,6 +443,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
Patches currently in longterm-queue-2.6.33 which might be from
xufeng.zh...@windriver.com are
/home/gregkh/linux/longterm/longterm-queue-2.6.33/queue-2.6.33/udp-recvmsg-clear-msg_trunc-flag-when-starting-over-for-a-new-packet.patch
/home/gregkh/linux/longterm/longterm-queue-2.6.33/queue-2.6.33/ipv6-udp-use-the-correct-variable-to-determine-non-blocking-condition.patch
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