From patchwork Tue Oct 6 00:06:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Simmons X-Patchwork-Id: 11817947 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 07FD0112E for ; Tue, 6 Oct 2020 00:07:48 +0000 (UTC) Received: from pdx1-mailman02.dreamhost.com (pdx1-mailman02.dreamhost.com [64.90.62.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CA380206F4 for ; Tue, 6 Oct 2020 00:07:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA380206F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lustre-devel-bounces@lists.lustre.org Received: from pdx1-mailman02.dreamhost.com (localhost [IPv6:::1]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id A1C3821FD08; Mon, 5 Oct 2020 17:07:13 -0700 (PDT) X-Original-To: lustre-devel@lists.lustre.org Delivered-To: lustre-devel-lustre.org@pdx1-mailman02.dreamhost.com Received: from smtp4.ccs.ornl.gov (smtp4.ccs.ornl.gov [160.91.203.40]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id 200AA21FFD2 for ; Mon, 5 Oct 2020 17:06:39 -0700 (PDT) Received: from star.ccs.ornl.gov (star.ccs.ornl.gov [160.91.202.134]) by smtp4.ccs.ornl.gov (Postfix) with ESMTP id 6914C10087FA; Mon, 5 Oct 2020 20:06:25 -0400 (EDT) Received: by star.ccs.ornl.gov (Postfix, from userid 2004) id 64CFB2F0E6; Mon, 5 Oct 2020 20:06:25 -0400 (EDT) From: James Simmons To: Andreas Dilger , Oleg Drokin , NeilBrown Date: Mon, 5 Oct 2020 20:06:17 -0400 Message-Id: <1601942781-24950-39-git-send-email-jsimmons@infradead.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1601942781-24950-1-git-send-email-jsimmons@infradead.org> References: <1601942781-24950-1-git-send-email-jsimmons@infradead.org> Subject: [lustre-devel] [PATCH 38/42] lnet: deadlock on LNet shutdown X-BeenThere: lustre-devel@lists.lustre.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "For discussing Lustre software development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Serguei Smirnov , Lustre Development List MIME-Version: 1.0 Errors-To: lustre-devel-bounces@lists.lustre.org Sender: "lustre-devel" From: Serguei Smirnov Release ln_api_mutex during LNet shutdown while waiting for zombie LNI to allow other threads to read the LNet state updated by the shutdown and fall through, avoiding the deadlock WC-bug-id: https://jira.whamcloud.com/browse/LU-12233 Lustre-commit: e0c445648a38fb ("LU-12233 lnet: deadlock on LNet shutdown") Signed-off-by: Serguei Smirnov Reviewed-on: https://review.whamcloud.com/39933 Reviewed-by: Chris Horn Reviewed-by: Amir Shehata Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- net/lnet/lnet/api-ni.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/lnet/lnet/api-ni.c b/net/lnet/lnet/api-ni.c index f678ae2..03473bf 100644 --- a/net/lnet/lnet/api-ni.c +++ b/net/lnet/lnet/api-ni.c @@ -2036,13 +2036,21 @@ static void lnet_push_target_fini(void) } if (!list_empty(&ni->ni_netlist)) { + /* Unlock mutex while waiting to allow other + * threads to read the LNet state and fall through + * to avoid deadlock + */ lnet_net_unlock(LNET_LOCK_EX); + mutex_unlock(&the_lnet.ln_api_mutex); + ++i; if ((i & (-i)) == i) { CDEBUG(D_WARNING, "Waiting for zombie LNI %s\n", libcfs_nid2str(ni->ni_nid)); } schedule_timeout_uninterruptible(HZ); + + mutex_lock(&the_lnet.ln_api_mutex); lnet_net_lock(LNET_LOCK_EX); continue; }