[PATCH 1/2] arm64/pageattr: Propagate return value from __change_memory_common

[Yang Shi]

On 11/13/25 3:55 AM, Ryan Roberts wrote:
> On 12/11/2025 06:27, Dev Jain wrote:
>> The rodata=on security measure requires that any code path which does
>> vmalloc -> set_memory_ro/set_memory_rox must protect the linear map alias
>> too. Therefore, if such a call fails, we must abort set_memory_* and caller
>> must take appropriate action; currently we are suppressing the error, and
>> there is a real chance of such an error arising post commit a166563e7ec3
>> ("arm64: mm: support large block mapping when rodata=full"). Therefore,
>> propagate any error to the caller.
>>
>> Fixes: a166563e7ec3 ("arm64: mm: support large block mapping when rodata=full")
>> Signed-off-by: Dev Jain <dev.jain at arm.com>
> Reviewed-by: Ryan Roberts <ryan.roberts at arm.com>
>
> It would be good to get this into v6.18 I guess?

Yeah, agreed.

>
> Although I think this will conflict with a patch from Yang that makes this work
> with a partial vm area range - But I think that one will only go to v6.19.

Yes, it will conflict. But it is quite easy to solve. I will rebase my 
patch on top of it once it is picked.

Thanks,
Yang

>
> Thanks,
> Ryan
>
>> ---
>> v1 of this patch: https://lore.kernel.org/all/20251103061306.82034-1-dev.jain@arm.com/
>> I have dropped stable since no real chance of failure was there.
>>
>>   arch/arm64/mm/pageattr.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
>> index 5135f2d66958..b4ea86cd3a71 100644
>> --- a/arch/arm64/mm/pageattr.c
>> +++ b/arch/arm64/mm/pageattr.c
>> @@ -148,6 +148,7 @@ static int change_memory_common(unsigned long addr, int numpages,
>>   	unsigned long size = PAGE_SIZE * numpages;
>>   	unsigned long end = start + size;
>>   	struct vm_struct *area;
>> +	int ret;
>>   	int i;
>>   
>>   	if (!PAGE_ALIGNED(addr)) {
>> @@ -185,8 +186,10 @@ static int change_memory_common(unsigned long addr, int numpages,
>>   	if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
>>   			    pgprot_val(clear_mask) == PTE_RDONLY)) {
>>   		for (i = 0; i < area->nr_pages; i++) {
>> -			__change_memory_common((u64)page_address(area->pages[i]),
>> +			ret = __change_memory_common((u64)page_address(area->pages[i]),
>>   					       PAGE_SIZE, set_mask, clear_mask);
>> +			if (ret)
>> +				return ret;
>>   		}
>>   	}
>>