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From: Himanshu Madhani <hmadhani@marvell.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: "<James.Bottomley@hansenpartnership.com>" 
	<James.Bottomley@HansenPartnership.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [EXT] [PATCH 4/8] qla2xxx: Fix driver unload hang
Date: Fri, 8 Nov 2019 23:38:29 +0000	[thread overview]
Message-ID: <1516C4D6-198B-45E1-82E8-5FDE39BEDAEB@marvell.com> (raw)
In-Reply-To: <cff0bb9a-4495-1064-dffc-5a15dcb30dbd@acm.org>

Hi Bart, 

> On Nov 7, 2019, at 12:30 PM, Bart Van Assche <bvanassche@acm.org> wrote:
> 
> External Email
> 
> ----------------------------------------------------------------------
> 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?
> 
> 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 while loop into something like the following:
> 
> 	if (atomic_read(&qpair->ref_count))
> 		msleep(500);
> 	WARN_ON_ONCE(atomic_read(&qpair->ref_count));
> 
> Thanks,
> 
> 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 your suggestion to verify if adding WARN_ON_ONCE will make any difference. If we discover that adding WARN_ON_ONCE indeed helps, then I will add a patch with fixes tag during rc window. 

Let me know if you disagree. 

Thanks,
Himanshu

  reply	other threads:[~2019-11-08 23:38 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05 15:06 [PATCH 0/8] qla2xxx: Bug Fixes for the driver Himanshu Madhani
2019-11-05 15:06 ` [PATCH 1/8] qla2xxx: Retry PLOGI on FC-NVMe PRLI failure Himanshu Madhani
2019-11-05 15:18   ` Ewan D. Milne
2019-11-05 15:06 ` [PATCH 2/8] qla2xxx: Do command completion on abort timeout Himanshu Madhani
2019-11-05 15:18   ` Ewan D. Milne
2019-11-05 16:57   ` Bart Van Assche
2019-11-07 16:46     ` [EXT] " Himanshu Madhani
2019-11-05 15:06 ` [PATCH 3/8] qla2xxx: Fix SRB leak on switch command timeout Himanshu Madhani
2019-11-05 15:19   ` Ewan D. Milne
2019-11-05 15:06 ` [PATCH 4/8] qla2xxx: Fix driver unload hang Himanshu Madhani
2019-11-05 15:19   ` Ewan D. Milne
2019-11-07 16:54   ` Bart Van Assche
     [not found]     ` <83CC0DDF-4907-41A2-91EC-1569A07A6BA9@marvell.com>
2019-11-07 17:58       ` Bart Van Assche
2019-11-07 18:30         ` Bart Van Assche
2019-11-08 23:38           ` Himanshu Madhani [this message]
2019-11-08 23:58             ` [EXT] " Bart Van Assche
2019-11-05 15:06 ` [PATCH 5/8] qla2xxx: Fix double scsi_done for abort path Himanshu Madhani
2019-11-05 15:20   ` Ewan D. Milne
2019-11-07 18:01   ` Bart Van Assche
2019-11-05 15:06 ` [PATCH 6/8] qla2xxx: Fix memory leak when sending I/O fails Himanshu Madhani
2019-11-05 15:20   ` Ewan D. Milne
2019-11-18 20:25   ` Himanshu Madhani
2019-11-19  5:02     ` Martin K. Petersen
2019-11-05 15:06 ` [PATCH 7/8] qla2xxx: Fix device connect issues in P2P configuration Himanshu Madhani
2019-11-05 15:21   ` Ewan D. Milne
2019-11-05 15:06 ` [PATCH 8/8] qla2xxx: Update driver version to 10.01.00.21-k Himanshu Madhani
2019-11-05 15:21   ` Ewan D. Milne
2019-11-09  2:16 ` [PATCH 0/8] qla2xxx: Bug Fixes for the driver Martin K. Petersen

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