Re: [PATCH v2] powerpc/fadump: define MIN_RMA in bytes value to fix overflow

[Sayali Patil <sayalip@linux.ibm.com>]

On 15/06/26 15:06, Ritesh Harjani (IBM) wrote:
> Sayali Patil <sayalip@linux.ibm.com> writes:
> 
>> The MIN_RMA size checks in fadump_setup_param_area() use
>> (MIN_RMA * 1024 * 1024), which is evaluated in int and can
>> overflow when MIN_RMA is increased to values such as SZ_2G.
>> This triggers compiler warnings such as:
>>
>> warning: integer overflow in expression of type 'int'
>> results in '0' [-Woverflow]
>>
>> Define MIN_RMA directly in bytes using SZ_1M and update the
>> callers accordingly. This avoids repeated unit conversions and
>> prevents integer overflow.
>>
>> Also convert MIN_RMA back to MB when populating the firmware
>> architecture vector, since firmware expects the value in MB.
>>
>> Fixes: b7bb46062457 ("powerpc/fadump: fix additional param memory reservation for HASH MMU")
> 
> Since this is not a bug per-se, so we need not add a Fixes tag.
> But while we are at it, we may correct the commit subject to...
> 
>      powerpc/fadump: Define MIN_RMA in bytes rather than MB
> 
> ... since there is no overflow with it's current value.
> 
> With the above changes in place, feel free to add:
> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> 
> 
Sent out v3 incorporating the requested changes.
V3: 
https://lore.kernel.org/all/310b040acef712fdc79e3e37d0f4c2213938b556.1781589284.git.sayalip@linux.ibm.com/

Thanks,
Sayali