Re: [PATCH] powerpc/fadump: reset dump area size variable if memblock reserve fails

[Michael Ellerman <mpe@ellerman.id.au>]

Sourabh Jain <sourabhjain@linux.ibm.com> writes:
> Hello Michael,
>
> Do you have any feedback or comments regarding this patch?
>
> Thanks,
> Sourabh
>
> On 08/06/23 14:52, Sourabh Jain wrote:
>> If the memory reservation process (memblock_reserve) fails to reserve
>> the memory, the reserve dump variable retains the dump area size.
>> Consequently, the size of the dump area calculated for reservation
>> is displayed in /sys/kernel/fadump/mem_reserved.
>>
>> To resolve this issue, the reserve dump area size variable is set to 0
>> if the memblock_reserve fails to reserve memory.
>>
>> Fixes: 8255da95e545 ("powerpc/fadump: release all the memory above boot memory size")
>> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
>> Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
>> ---
>>   arch/powerpc/kernel/fadump.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
>> index ea0a073abd96..a8f2c3b2fa1e 100644
>> --- a/arch/powerpc/kernel/fadump.c
>> +++ b/arch/powerpc/kernel/fadump.c
>> @@ -641,6 +641,7 @@ int __init fadump_reserve_mem(void)
>>   			goto error_out;
>>   
>>   		if (memblock_reserve(base, size)) {
>> +			fw_dump.reserve_dump_area_size = 0;
>>   			pr_err("Failed to reserve memory!\n");
>>   			goto error_out;
>>   		}

Shouldn't reserve_dump_area_size be set to zero at error_out, which
already clears fadump_enabled?

	return ret;
error_out:
	fw_dump.fadump_enabled = 0;
	return 0;
}


Otherwise the code immediately above will suffer from the same issue
won't it?

		if (fw_dump.ops->fadump_setup_metadata &&
		    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
			goto error_out;

cheers