From patchwork Wed Dec 12 05:09:54 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [3.5.y.z, extended, stable] Patch "RDS: fix rds-ping spinlock recursion" has been added to staging queue Date: Tue, 11 Dec 2012 19:09:54 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 205391 Message-Id: <1355288994-29920-1-git-send-email-herton.krzesinski@canonical.com> To: "jeff.liu" Cc: Venkat Venkatsubra , kernel-team@lists.ubuntu.com, James Morris , "David S. Miller" , Dan Carpenter This is a note to let you know that I have just added a patch titled RDS: fix rds-ping spinlock recursion to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ >From 27ec01ca8e6ad143bd80219551a7ef306cc1154a Mon Sep 17 00:00:00 2001 From: "jeff.liu" Date: Mon, 8 Oct 2012 18:57:27 +0000 Subject: [PATCH] RDS: fix rds-ping spinlock recursion commit 5175a5e76bbdf20a614fb47ce7a38f0f39e70226 upstream. 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 CC: Venkat Venkatsubra CC: David S. Miller CC: James Morris Signed-off-by: Jie Liu Signed-off-by: David S. Miller Signed-off-by: Herton Ronaldo Krzesinski --- net/rds/send.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 1.7.9.5 diff --git a/net/rds/send.c b/net/rds/send.c index 96531d4..88eace5 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;