Re: [PATCH] iommu: check if group is NULL before remove device

[Frank Wunderlich]

Hi Joerg,

Sorry for late reply, somehow i marked message as read without answering it.

Am 15. Juli 2021 09:20:04 MESZ schrieb Joerg Roedel <joro@xxxxxxxxxx>:
>On Thu, Jul 15, 2021 at 09:11:50AM +0200, Frank Wunderlich wrote:
>> From: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx>
>> 
>> if probe is failing, iommu_group may be not initialized,
>
>Sentences start with capital letters.
>
>IOMMU patch subjects too, after the 'iommu:' prefix.

Will fix these in v2

>> so freeing it will result in NULL pointer access
>
>Please describe in more detail how this NULL-ptr dereference is
>triggered.

I had this by testing this series: 
https://patchwork.kernel.org/project/linux-mediatek/list/?series=515129

Initialization in mtk driver was failed (i guess the iommu group was not yet created), cleanup was started and so this function is called with a NULL group pointer. I can try to find my debug-trace if you need a kind of backtrace.

regards Frank