From patchwork Wed Nov 26 17:04:02 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: dann frazier X-Patchwork-Id: 10956 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 9921EDDD0C for ; Thu, 27 Nov 2008 04:04:11 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752866AbYKZREJ (ORCPT ); Wed, 26 Nov 2008 12:04:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752477AbYKZREI (ORCPT ); Wed, 26 Nov 2008 12:04:08 -0500 Received: from g1t0029.austin.hp.com ([15.216.28.36]:4074 "EHLO g1t0029.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752186AbYKZREG (ORCPT ); Wed, 26 Nov 2008 12:04:06 -0500 Received: from g4t0009.houston.hp.com (g4t0009.houston.hp.com [16.234.32.26]) by g1t0029.austin.hp.com (Postfix) with ESMTP id CA124380F7; Wed, 26 Nov 2008 17:04:04 +0000 (UTC) Received: from ldl.fc.hp.com (ldl.fc.hp.com [15.11.146.30]) by g4t0009.houston.hp.com (Postfix) with ESMTP id 72CCFC056; Wed, 26 Nov 2008 17:04:04 +0000 (UTC) Received: from localhost (ldl.fc.hp.com [127.0.0.1]) by ldl.fc.hp.com (Postfix) with ESMTP id 052AA39C07E; Wed, 26 Nov 2008 10:04:04 -0700 (MST) X-Virus-Scanned: Debian amavisd-new at ldl.fc.hp.com Received: from ldl.fc.hp.com ([127.0.0.1]) by localhost (ldl.fc.hp.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id d45fWwfYmxRX; Wed, 26 Nov 2008 10:04:02 -0700 (MST) Received: from krebs (krebs.dannf [10.8.0.7]) by ldl.fc.hp.com (Postfix) with ESMTP id 84AA539C078; Wed, 26 Nov 2008 10:04:02 -0700 (MST) Received: by krebs (Postfix, from userid 20800) id 763C03B624A; Wed, 26 Nov 2008 10:04:02 -0700 (MST) Date: Wed, 26 Nov 2008 10:04:02 -0700 From: dann frazier To: David Miller Cc: netdev@vger.kernel.org, eteo@redhat.com Subject: [PATCH] Fix soft lockups/OOM issues w/ unix garbage collector Message-ID: <20081126170401.GC30297@ldl.fc.hp.com> References: <20081120220326.GE24416@ldl.fc.hp.com> <20081125231712.GA30297@ldl.fc.hp.com> <20081125.211913.114802735.davem@davemloft.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20081125.211913.114802735.davem@davemloft.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This is an implementation of David Miller's suggested fix in: https://bugzilla.redhat.com/show_bug.cgi?id=470201 It has been updated to use wait_event() instead of wait_event_interruptible(). Paraphrasing the description from the above report, it makes sendmsg() block while UNIX garbage collection is in progress. This avoids a situation where child processes continue to queue new FDs over a AF_UNIX socket to a parent which is in the exit path and running garbage collection on these FDs. This contention can result in soft lockups and oom-killing of unrelated processes. Signed-off-by: dann frazier --- include/net/af_unix.h | 1 + net/unix/af_unix.c | 2 ++ net/unix/garbage.c | 13 ++++++++++--- 3 files changed, 13 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/include/net/af_unix.h b/include/net/af_unix.h index c29ff1d..1614d78 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -9,6 +9,7 @@ extern void unix_inflight(struct file *fp); extern void unix_notinflight(struct file *fp); extern void unix_gc(void); +extern void wait_for_unix_gc(void); #define UNIX_HASH_SIZE 256 diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index eb90f77..66d5ac4 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1343,6 +1343,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, if (NULL == siocb->scm) siocb->scm = &tmp_scm; + wait_for_unix_gc(); err = scm_send(sock, msg, siocb->scm); if (err < 0) return err; @@ -1493,6 +1494,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, if (NULL == siocb->scm) siocb->scm = &tmp_scm; + wait_for_unix_gc(); err = scm_send(sock, msg, siocb->scm); if (err < 0) return err; diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 6d4a9a8..abb3ab3 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -80,6 +80,7 @@ #include #include #include +#include #include #include @@ -91,6 +92,7 @@ static LIST_HEAD(gc_inflight_list); static LIST_HEAD(gc_candidates); static DEFINE_SPINLOCK(unix_gc_lock); +static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait); unsigned int unix_tot_inflight; @@ -266,12 +268,16 @@ static void inc_inflight_move_tail(struct unix_sock *u) list_move_tail(&u->link, &gc_candidates); } -/* The external entry point: unix_gc() */ +static bool gc_in_progress = false; -void unix_gc(void) +void wait_for_unix_gc(void) { - static bool gc_in_progress = false; + wait_event(unix_gc_wait, gc_in_progress == false); +} +/* The external entry point: unix_gc() */ +void unix_gc(void) +{ struct unix_sock *u; struct unix_sock *next; struct sk_buff_head hitlist; @@ -376,6 +382,7 @@ void unix_gc(void) /* All candidates should have been detached by now. */ BUG_ON(!list_empty(&gc_candidates)); gc_in_progress = false; + wake_up(&unix_gc_wait); out: spin_unlock(&unix_gc_lock);