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authorEric Dumazet <edumazet@google.com>2015-05-30 09:16:53 -0700
committerDavid S. Miller <davem@davemloft.net>2015-05-31 21:42:18 -0700
commitbeb39db59d14990e401e235faf66a6b9b31240b0 (patch)
tree872c5e11dfe18f09da783919375d53544cf06dd8 /net
parent9eb0a5d1905235b968dce5c1fda294ac2663d840 (diff)
downloadlinux-linaro-stable-beb39db59d14990e401e235faf66a6b9b31240b0.tar.gz
udp: fix behavior of wrong checksums
We have two problems in UDP stack related to bogus checksums : 1) We return -EAGAIN to application even if receive queue is not empty. This breaks applications using edge trigger epoll() 2) Under UDP flood, we can loop forever without yielding to other processes, potentially hanging the host, especially on non SMP. This patch is an attempt to make things better. We might in the future add extra support for rt applications wanting to better control time spent doing a recv() in a hostile environment. For example we could validate checksums before queuing packets in socket receive queue. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/udp.c6
-rw-r--r--net/ipv6/udp.c6
2 files changed, 4 insertions, 8 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d10b7e0112eb..1c92ea67baef 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1345,10 +1345,8 @@ csum_copy_err:
}
unlock_sock_fast(sk, slow);
- if (noblock)
- return -EAGAIN;
-
- /* starting over for a new packet */
+ /* starting over for a new packet, but check if we need to yield */
+ cond_resched();
msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index c2ec41617a35..e51fc3eee6db 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -525,10 +525,8 @@ csum_copy_err:
}
unlock_sock_fast(sk, slow);
- if (noblock)
- return -EAGAIN;
-
- /* starting over for a new packet */
+ /* starting over for a new packet, but check if we need to yield */
+ cond_resched();
msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}