From owner-svn-src-stable@freebsd.org Mon Nov 23 17:26:21 2015 Return-Path: Delivered-To: svn-src-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A513AA32880; Mon, 23 Nov 2015 17:26:21 +0000 (UTC) (envelope-from jimharris@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 635B11C80; Mon, 23 Nov 2015 17:26:21 +0000 (UTC) (envelope-from jimharris@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id tANHQKLf048758; Mon, 23 Nov 2015 17:26:20 GMT (envelope-from jimharris@FreeBSD.org) Received: (from jimharris@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id tANHQKs8048757; Mon, 23 Nov 2015 17:26:20 GMT (envelope-from jimharris@FreeBSD.org) Message-Id: <201511231726.tANHQKs8048757@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: jimharris set sender to jimharris@FreeBSD.org using -f From: Jim Harris Date: Mon, 23 Nov 2015 17:26:20 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r291213 - stable/10/sys/dev/nvme X-SVN-Group: stable-10 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Nov 2015 17:26:21 -0000 Author: jimharris Date: Mon Nov 23 17:26:20 2015 New Revision: 291213 URL: https://svnweb.freebsd.org/changeset/base/291213 Log: MFC r290198: nvme: fix race condition in split bio completion path Sponsored by: Intel Modified: stable/10/sys/dev/nvme/nvme_ns.c Modified: stable/10/sys/dev/nvme/nvme_ns.c ============================================================================== --- stable/10/sys/dev/nvme/nvme_ns.c Mon Nov 23 17:09:35 2015 (r291212) +++ stable/10/sys/dev/nvme/nvme_ns.c Mon Nov 23 17:26:20 2015 (r291213) @@ -239,7 +239,7 @@ static void nvme_bio_child_inbed(struct bio *parent, int bio_error) { struct nvme_completion parent_cpl; - int inbed; + int children, inbed; if (bio_error != 0) { parent->bio_flags |= BIO_ERROR; @@ -248,10 +248,13 @@ nvme_bio_child_inbed(struct bio *parent, /* * atomic_fetchadd will return value before adding 1, so we still - * must add 1 to get the updated inbed number. + * must add 1 to get the updated inbed number. Save bio_children + * before incrementing to guard against race conditions when + * two children bios complete on different queues. */ + children = atomic_load_acq_int(&parent->bio_children); inbed = atomic_fetchadd_int(&parent->bio_inbed, 1) + 1; - if (inbed == parent->bio_children) { + if (inbed == children) { bzero(&parent_cpl, sizeof(parent_cpl)); if (parent->bio_flags & BIO_ERROR) parent_cpl.status.sc = NVME_SC_DATA_TRANSFER_ERROR;