From nobody Thu May 15 13:55:21 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1508334830409823.6383363093989; Wed, 18 Oct 2017 06:53:50 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C8E0049034; Wed, 18 Oct 2017 13:53:48 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F3CEB6A519; Wed, 18 Oct 2017 13:53:47 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id B9EE91800CA1; Wed, 18 Oct 2017 13:53:47 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id v9IDrkXD009951 for ; Wed, 18 Oct 2017 09:53:46 -0400 Received: by smtp.corp.redhat.com (Postfix) id 3630891D8E; Wed, 18 Oct 2017 13:53:46 +0000 (UTC) Received: from beluga.usersys.redhat.com (unknown [10.43.2.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7AF3199E1D; Wed, 18 Oct 2017 13:53:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C8E0049034 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=libvir-list-bounces@redhat.com From: Erik Skultety To: libvir-list@redhat.com Date: Wed, 18 Oct 2017 15:52:31 +0200 Message-Id: In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-loop: libvir-list@redhat.com Cc: Erik Skultety Subject: [libvirt] [PATCH v6 9/9] nodedev: udev: Hook up virFileWaitForAccess to work around uevent race X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 18 Oct 2017 13:53:49 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" If we find ourselves in the situation that the 'add' uevent has been fired earlier than the sysfs tree for a device was created, we should use the best-effort approach and give kernel some predetermined amount of time, thus waiting for the attributes to be ready rather than discarding the device from our device list forever. If those don't appear in the given time frame, we need to move on, since libvirt can't wait indefinitely. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=3D1463285 Signed-off-by: Erik Skultety --- src/node_device/node_device_udev.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_devi= ce_udev.c index 9fa90257e..6686d4f3f 100644 --- a/src/node_device/node_device_udev.c +++ b/src/node_device/node_device_udev.c @@ -1188,9 +1188,23 @@ udevProcessMediatedDevice(struct udev_device *dev, char *canonicalpath =3D NULL; virNodeDevCapMdevPtr data =3D &def->caps->data.mdev; =20 - if (virAsprintf(&linkpath, "%s/mdev_type", udev_device_get_syspath(dev= )) < 0) + /* Because of a kernel uevent race, we might get the 'add' event prior= to + * the sysfs tree being ready, so any attempt to access any sysfs attr= ibute + * would result in ENOENT and us dropping the device, so let's work ar= ound + * it by waiting for the attributes to become available. + */ + + if (virAsprintf(&linkpath, "%s/mdev_type", + udev_device_get_syspath(dev)) < 0) goto cleanup; =20 + if (virFileWaitForExists(linkpath, 1, 100) < 0) { + virReportSystemError(errno, + _("failed to wait for file '%s' to appear"), + linkpath); + goto cleanup; + } + if (virFileResolveLink(linkpath, &canonicalpath) < 0) { virReportSystemError(errno, _("failed to resolve '%s'"), linkpath); goto cleanup; --=20 2.13.6 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list