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

From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Biggers <ebiggers@kernel.org>,
	<linux-fsdevel@vger.kernel.org>, "Chris Mason" <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>, <linux-btrfs@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/2] fs: clear a UBSAN shift-out-of-bounds warning
Date: Fri, 25 Nov 2022 16:33:14 +0800	[thread overview]
Message-ID: <6660724c-46e8-87b7-e382-51789953242d@huawei.com> (raw)
In-Reply-To: <Y4BkJd3Jy6MY3cdu@ZenIV>

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