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Petersen" , "linux-scsi@vger.kernel.org" Subject: Re: [EXT] [PATCH 4/8] qla2xxx: Fix driver unload hang Thread-Topic: [EXT] [PATCH 4/8] qla2xxx: Fix driver unload hang Thread-Index: AQHVlo2f7OgiXp46aEiT1/1V3GOGrA== Date: Fri, 8 Nov 2019 23:38:29 +0000 Message-ID: <1516C4D6-198B-45E1-82E8-5FDE39BEDAEB@marvell.com> References: <20191105150657.8092-1-hmadhani@marvell.com> <20191105150657.8092-5-hmadhani@marvell.com> <83CC0DDF-4907-41A2-91EC-1569A07A6BA9@marvell.com> <10b38f34-128a-fd71-1542-9025dc107f62@acm.org> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3445.104.11) x-originating-ip: [2600:1700:211:eb30:759a:ca40:26ef:315c] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 22d92a10-c584-4852-6477-08d764a4c254 x-ms-traffictypediagnostic: MN2PR18MB3085: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 0215D7173F x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(4636009)(366004)(136003)(396003)(376002)(39860400002)(346002)(199004)(189003)(51444003)(86362001)(6116002)(305945005)(71190400001)(71200400001)(6506007)(7736002)(478600001)(6512007)(8676002)(14444005)(76176011)(4326008)(2906002)(6486002)(6916009)(6436002)(81166006)(81156014)(99286004)(256004)(50226002)(316002)(446003)(229853002)(64756008)(53546011)(66476007)(66556008)(66446008)(33656002)(76116006)(91956017)(25786009)(5660300002)(6246003)(486006)(476003)(2616005)(186003)(102836004)(46003)(11346002)(8936002)(66946007)(14454004)(36756003);DIR:OUT;SFP:1101;SCL:1;SRVR:MN2PR18MB3085;H:MN2PR18MB2719.namprd18.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: marvell.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: uJPd0r6nUHTPANcBlLud5cuzOdD7/lzTggnM+Xoa4R5VK+BaYiu4yYj+Hd3LaxVOQCpLkE4CZhrLDE9H+I0teyl1YN8POTXHa0H/mTEvRP8rntAkW3Idy5tr91p8aP/ITHkswAy1Z4ahgw+GNxI0tvGjqcR+qs+fr/Kx1d6KLQ9FfTbrMnvnIEdZvV++Q18gC1Bu1EOa6ulryAAQ8jb7dO9naOUSoR46AF5yUzqtS8q3vUALsBumWo8+h2ZSOTbuDJcuRgNyp08mGtJILY875k+R8W3njq2icLd1jqpiwo4nqf8MUjazPq7OGeZX8cQFTSF0MMlNT/fWS++BtRCVPPYqU3XVhA82vbTf1z4bDnHp5Z/Yl5e7JrbHTTCzCU0w8wZGGwZ8B/kmwWTetkrudsZdcrcJGU+u2Ww21dnl/rr53XHQ55rTPxiSHqgbKjmD x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 22d92a10-c584-4852-6477-08d764a4c254 X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Nov 2019 23:38:29.3409 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 70e1fb47-1155-421d-87fc-2e58f638b6e0 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: L3fLDdGmuA9fQ56CIw33kv6CtG7iCoAKIvz0LlsczePXIhX9oXtv5km3ghSFOD8fbdr8EEtO9bBxsBGo47Vaqg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR18MB3085 X-OriginatorOrg: marvell.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-11-08_09:2019-11-08,2019-11-08 signatures=0 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi Bart,=20 > On Nov 7, 2019, at 12:30 PM, Bart Van Assche wrote: >=20 > External Email >=20 > ---------------------------------------------------------------------- > On 11/7/19 9:58 AM, Bart Van Assche wrote: >> Does your answer mean that this hang has not yet been root-caused fully >> and hence that it is possible this patch is only a workaround but not a >> fix of the root cause? >=20 > Answering my own question: I think that a qpair refcount leak is a severe= problem and not something that should be ignored. How about changing the w= hile loop into something like the following: >=20 > if (atomic_read(&qpair->ref_count)) > msleep(500); > WARN_ON_ONCE(atomic_read(&qpair->ref_count)); >=20 > Thanks, >=20 > Bart. Since we had seen this hang in a specific cluster environment and refcount = leak was observed, I would like to add this patch as is and will consider y= our suggestion to verify if adding WARN_ON_ONCE will make any difference. I= f we discover that adding WARN_ON_ONCE indeed helps, then I will add a patc= h with fixes tag during rc window.=20 Let me know if you disagree.=20 Thanks, Himanshu=