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SubjectRe: [PATCH v3 0/2] fs: clear a UBSAN shift-out-of-bounds warning
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On 2022/11/26 5:00, Al Viro wrote:
> On Fri, Nov 25, 2022 at 05:13:56PM +0800, Zhen Lei wrote:
>> v2 --> v3:
>> Updated the commit message of patch 2/2 based on Alexander Viro's suggestion.
>
> Not exactly what I meant... I've tentatively applied it, with the

Haha, I felt like something was missing yesterday, too. But as far as my English
level is concerned, I usually copy the words suggested by others directly.

> following commit message:

Thanks.

>
> --------------------------------
> get rid of INT_LIMIT, use type_max() instead
>
> INT_LIMIT() tries to do what type_max() does, except that type_max()
> doesn't rely upon undefined behaviour[*], might as well use type_max()
> instead.
>
> [*] if T is an N-bit signed integer type, the maximal value in T is
> pow(2, N - 1) - 1, all right, but naive expression for that value
> ends up with a couple of wraparounds and as usual for wraparounds
> in signed types, that's an undefined behaviour. type_max() takes
> care to avoid those...
>
> Caught-by: UBSAN
> Suggested-by: Eric Biggers <ebiggers@kernel.org>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> Reviewed-by: Eric Biggers <ebiggers@google.com>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> --------------------------------
>
> Does anybody have objections against the commit message above?

Looks good to me.

>
> .
>

--
Regards,
Zhen Lei

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