Re: [PATCH v2 0/2] fs: clear a UBSAN shift-out-of-bounds warning

From: Leizhen (ThunderTown)
Date: Fri Nov 25 2022 - 03:33:23 EST




On 2022/11/25 14:43, Al Viro wrote:
> On Mon, Nov 21, 2022 at 10:44:16AM +0800, Zhen Lei wrote:
>> v1 -- > v2:
>> 1. Replace INT_LIMIT(loff_t) with OFFSET_MAX in btrfs.
>> 2. Replace INT_LIMIT() with type_max().
>
> Looks fine, except that I'd rather go for commit message
> along the lines of "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"

Very good. Do I send v3, or do you update it?

>
> If you want to credit UBSAN - sure, no problem, just don't
> clutter the commit message with that. As it is, it reads
> as "make $TOOL STFU"...

Okay, I'll pay attention next time. This USBAN problem is relatively
simple and can be located without relying on other information, so I
omitted the rest.

After changing to your suggested description, it seems that there is
no need to mention UBSAN, after all, it is just a false positive and
there is no real problem.

>
> .
>

--
Regards,
Zhen Lei