linux-kernel - Re: [PATCH v5 6/7] module: Improve support for asynchronous module exit code

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Message-ID: <d87e5f8c-c221-f5cb-0ae7-969867fbc9b5@acm.org>
Date:   Mon, 3 Oct 2022 17:24:03 -0700
From:   Bart Van Assche <bvanassche@....org>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Ming Lei <ming.lei@...hat.com>, Hannes Reinecke <hare@...e.de>,
        John Garry <john.garry@...wei.com>,
        Mike Christie <michael.christie@...cle.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-modules@...r.kernel.org, linux-kernel@...r.kernel.org,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        Tejun Heo <tj@...nel.org>
Subject: Re: [PATCH v5 6/7] module: Improve support for asynchronous module
 exit code

On 10/3/22 16:56, Luis Chamberlain wrote:
> Yeah I've gone ahead and re-read your original patch again the issue
> with that is it waits *once* for the refcnt to go to 0, but that does
> not forbit it from going back up, at which point you have a race which
> can still create the situation. Every subsystem is different, but for
> instance simply running a loop opening a device block file should
> suffice to bump the refcnt of a respective block driver module. So
> at least the patch itself won't ultimately address this issue I'm
> afraid.

Hi Luis,

Thanks for the feedback. I will try to find a solution that does not 
require to modify the kernel module code.

Bart.