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SubjectRe: [PATCH] x86/lib: Fix overflow of variable m when val >= 1410065408
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On 02/11/2023 16:38, Dave Hansen wrote:
> On 11/1/23 08:32, Colin Ian King wrote:
> ...
>> int num_digits(int val)
>> {
>> - int m = 10;
>> + long m = 10;
>> int d = 1;
>>
>> if (val < 0) {
>
> Isn't this still broken on 32-bit where sizeof(long) == sizeof(int)?
> Seems like we need 'm' to be able to hold values that are ~10x larger
> than 'val' if we need this to work for the entire int range.

Good point, long long is required for 32 bit,

sizes:
arch int long long long
i386 4 4 8
x86_64 4 8 8

I'll send a V2.


>
> Also, performance doesn't matter here at *all* with the current use in
> a couple of printk()'s. Just making 'm' 'long long' or u64 probably be
> just fine.

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