Re: [PATCH v1 4/4] xen/netback: Fix grant copy across page boundary with KASAN

[Sergey Dyasli]

On 09/01/2020 13:36, Paul Durrant wrote:
> On Wed, 8 Jan 2020 at 15:21, Sergey Dyasli <sergey.dyasli@xxxxxxxxxx> wrote:
>>
>> From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
>>
>> When KASAN (or SLUB_DEBUG) is turned on, the normal expectation that
>> allocations are aligned to the next power of 2 of the size does not
>> hold. Therefore, handle grant copies that cross page boundaries.
>>
>> Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
>> Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
>> ---
>> RFC --> v1:
>> - Added BUILD_BUG_ON to the netback patch
>> - xenvif_idx_release() now located outside the loop
>>
>> CC: Wei Liu <wei.liu@xxxxxxxxxx>
>> CC: Paul Durrant <paul@xxxxxxx>
> [snip]
>>
>> +static void __init __maybe_unused build_assertions(void)
>> +{
>> +       BUILD_BUG_ON(sizeof(struct xenvif_tx_cb) > 48);
>
> FIELD_SIZEOF(struct sk_buff, cb) rather than a magic '48' I think.

The macro got renamed recently, so now it should be:

    sizeof_field(struct sk_buff, cb))

Thanks for the suggestion.

--
Sergey