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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 3 Jul 2018 12:37:59 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w63BbwAT29425852 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 3 Jul 2018 11:37:58 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EA61D52059; Tue, 3 Jul 2018 14:38:23 +0100 (BST) Received: from marc-ibm.boeblingen.de.ibm.com (unknown [9.152.224.50]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id C465D5204F; Tue, 3 Jul 2018 14:38:23 +0100 (BST) From: Marc Hartmayer To: Date: Tue, 3 Jul 2018 13:37:33 +0200 In-Reply-To: <20180703113738.3425-1-mhartmay@linux.ibm.com> References: <20180703113738.3425-1-mhartmay@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18070311-0020-0000-0000-000002A29A37 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18070311-0021-0000-0000-000020EEB199 Message-Id: <20180703113738.3425-2-mhartmay@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-07-03_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=3 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807030134 X-Greylist: Sender passed SPF test, Sender IP whitelisted by DNSRBL, ACL 207 matched, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 03 Jul 2018 11:38:04 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 03 Jul 2018 11:38:04 +0000 (UTC) for IP:'148.163.158.5' DOMAIN:'mx0b-001b2d01.pphosted.com' HELO:'mx0a-001b2d01.pphosted.com' FROM:'mhartmay@linux.ibm.com' RCPT:'' X-RedHat-Spam-Score: -0.701 (RCVD_IN_DNSWL_LOW, SPF_PASS) 148.163.158.5 mx0b-001b2d01.pphosted.com 148.163.158.5 mx0b-001b2d01.pphosted.com X-Scanned-By: MIMEDefang 2.83 on 10.5.110.25 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-loop: libvir-list@redhat.com Cc: Erik Skultety Subject: [libvirt] [PATCH v2 1/6] rpc: Fix deadlock if there is no worker pool available 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 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 03 Jul 2018 11:38:13 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" @srv must be unlocked for the call virNetServerProcessMsg otherwise a deadlock can occur. Since the pointer 'srv->workers' will never be changed after initialization and the thread pool has it's own locking we can release the lock of 'srv' earlier. This also fixes the deadlock. Signed-off-by: Marc Hartmayer Reviewed-by: Boris Fiuczynski Reviewed-by: Bjoern Walk Reviewed-by: John Ferlan --- src/rpc/virnetserver.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c index 5c7f7dd08fe1..091e3ef23406 100644 --- a/src/rpc/virnetserver.c +++ b/src/rpc/virnetserver.c @@ -51,6 +51,7 @@ struct _virNetServer { =20 char *name; =20 + /* Immutable pointer, self-locking APIs */ virThreadPoolPtr workers; =20 char *mdnsGroupName; @@ -177,9 +178,11 @@ static void virNetServerHandleJob(void *jobOpaque, voi= d *opaque) VIR_FREE(job); } =20 -static void virNetServerDispatchNewMessage(virNetServerClientPtr client, - virNetMessagePtr msg, - void *opaque) + +static void +virNetServerDispatchNewMessage(virNetServerClientPtr client, + virNetMessagePtr msg, + void *opaque) { virNetServerPtr srv =3D opaque; virNetServerProgramPtr prog =3D NULL; @@ -196,6 +199,9 @@ static void virNetServerDispatchNewMessage(virNetServer= ClientPtr client, break; } } + /* we can unlock @srv since @prog can only become invalid in case + * of disposing @srv */ + virObjectUnlock(srv); =20 if (srv->workers) { virNetServerJobPtr job; @@ -223,15 +229,14 @@ static void virNetServerDispatchNewMessage(virNetServ= erClientPtr client, goto error; } =20 - virObjectUnlock(srv); return; =20 error: virNetMessageFree(msg); virNetServerClientClose(client); - virObjectUnlock(srv); } =20 + /** * virNetServerCheckLimits: * @srv: server to check limits on --=20 2.13.4 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list