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authorjeff.liu <jeff.liu@oracle.com>2012-10-08 18:57:27 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-28 10:56:17 -0700
commit0b5b763426e93ed843aad22101265f0f975e48a5 (patch)
tree1f237730b04d66b1597046784ab6c06d3d4b01fc
parentc4e6940cc12c1cac1e8664a2a46ef01f0783c69c (diff)
RDS: fix rds-ping spinlock recursion
[ Upstream commit 5175a5e76bbdf20a614fb47ce7a38f0f39e70226 ] This is the revised patch for fixing rds-ping spinlock recursion according to Venkat's suggestions. RDS ping/pong over TCP feature has been broken for years(2.6.39 to 3.6.0) since we have to set TCP cork and call kernel_sendmsg() between ping/pong which both need to lock "struct sock *sk". However, this lock has already been hold before rds_tcp_data_ready() callback is triggerred. As a result, we always facing spinlock resursion which would resulting in system panic. Given that RDS ping is only used to test the connectivity and not for serious performance measurements, we can queue the pong transmit to rds_wq as a delayed response. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> CC: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com> CC: David S. Miller <davem@davemloft.net> CC: James Morris <james.l.morris@oracle.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/rds/send.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/rds/send.c b/net/rds/send.c
index 96531d4033a2..88eace57dd6b 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -1122,7 +1122,7 @@ rds_send_pong(struct rds_connection *conn, __be16 dport)
rds_stats_inc(s_send_pong);
if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
- rds_send_xmit(conn);
+ queue_delayed_work(rds_wq, &conn->c_send_w, 0);
rds_message_put(rm);
return 0;