From: Marc Gonzalez <marc.w.gonzalez@free.fr>
To: Herbert Xu <herbert@gondor.apana.org.au>,
Chuhong Yuan <hslester96@gmail.com>
Cc: Jamie Iles <jamie@jamieiles.com>,
"David S . Miller" <davem@davemloft.net>,
linux-arm-kernel@lists.infradead.org,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] crypto: picoxcell: add missed tasklet_kill
Date: Fri, 22 Nov 2019 17:36:35 +0100 [thread overview]
Message-ID: <218e9053-42c7-098e-ecda-e0306361cc23@free.fr> (raw)
In-Reply-To: <20191122085512.m75tjfa3valqfgyv@gondor.apana.org.au>
On 22/11/2019 09:55, Herbert Xu wrote:
> On Fri, Nov 15, 2019 at 10:31:16AM +0800, Chuhong Yuan wrote:
>> This driver forgets to kill tasklet when probe fails and remove.
>> Add the calls to fix it.
>>
>> Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
>
> Yes this driver does look buggy but I think your patch isn't
> enough.
>
>> diff --git a/drivers/crypto/picoxcell_crypto.c b/drivers/crypto/picoxcell_crypto.c
>> index 3cbefb41b099..8d7c6bb2876e 100644
>> --- a/drivers/crypto/picoxcell_crypto.c
>> +++ b/drivers/crypto/picoxcell_crypto.c
>> @@ -1755,6 +1755,7 @@ static int spacc_probe(struct platform_device *pdev)
>> if (!ret)
>> return 0;
>>
>> + tasklet_kill(&engine->complete);
>
> The tasklet is schedule by the IRQ handler so you should not kill
> it until the IRQ handler has been unregistered.
>
> This driver is also buggy because it registers the IRQ handler
> before initialising the tasklet. You must always be prepared for
> spurious IRQs. IOW, as soon as you register the IRQ handler you
> must be prepared for it to be called.
>
>> @@ -1771,6 +1772,7 @@ static int spacc_remove(struct platform_device *pdev)
>> struct spacc_alg *alg, *next;
>> struct spacc_engine *engine = platform_get_drvdata(pdev);
>>
>> + tasklet_kill(&engine->complete);
>
> Ditto.
>
> However, the IRQ handler is registered through devm which makes it
> hard to kill the tasklet after unregistering it. We should probably
> convert it to a normal request_irq so we can control how it's
> unregistered.
Or inversely, registering the tasklet_kill() through devm, so that it
is called *after* the ISR unregistration.
Regards.
next prev parent reply other threads:[~2019-11-22 16:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 2:31 [PATCH] crypto: picoxcell: add missed tasklet_kill Chuhong Yuan
2019-11-22 8:55 ` Herbert Xu
2019-11-22 16:36 ` Marc Gonzalez [this message]
2019-11-22 23:27 ` Herbert Xu
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