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From: Miles Chen <miles.chen@mediatek.com>
To: <robin.murphy@arm.com>
Cc: <angelogioacchino.delregno@collabora.com>,
	<hverkuil-cisco@xs4all.nl>, <iommu@lists.linux-foundation.org>,
	<joro@8bytes.org>, <jroedel@suse.de>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-mediatek@lists.infradead.org>, <matthias.bgg@gmail.com>,
	<mchehab@kernel.org>, <miles.chen@mediatek.com>,
	<will@kernel.org>, <yong.wu@mediatek.com>
Subject: Re: [PATCH v2] iommu/mediatek: fix NULL pointer dereference when printing dev_name
Date: Wed, 27 Apr 2022 10:13:08 +0800	[thread overview]
Message-ID: <20220427021308.22855-1-miles.chen@mediatek.com> (raw)
In-Reply-To: <9debe3ab-603d-0d30-a6aa-8963b48e83d4@arm.com>

hi Robin,

>> -	link = device_link_add(dev, larbdev,
>> -			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
>> -	if (!link)
>> -		dev_err(dev, "Unable to link %s\n", dev_name(larbdev));
>> +	if (larbdev) {
>
>Until the MT8195 infra MMU support lands, is there ever a case where 
>it's actually valid for larbdev to be NULL? If not, I think it would be 
>a lot clearer to explicitly fail the probe here, rather than silently 
>continue and risk fatal errors, hangs, or other weird behaviour if 
>there's no guarantee that the correct LARB is powered up (plus then the 
>release callbacks wouldn't need to worry about it either).

Thanks, I will do probe fail in patch v3 and remove the release modification.

thanks,
Miles

>
>Robin.


      parent reply	other threads:[~2022-04-27  2:13 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-25  8:24 Miles Chen
2022-04-25 10:03 ` Robin Murphy
2022-04-26  5:52   ` Yong Wu
2022-04-27  2:13     ` Miles Chen
2022-04-27  2:13   ` Miles Chen [this message]

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