linux-kernel - Re: [PATCH] fs: fuse: check return value of fuse_simple

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Date:   Wed, 22 Jan 2020 15:56:05 +0300
From:   Cengiz Can <cengiz@...nel.wtf>
To:     Miklos Szeredi <miklos@...redi.hu>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fs: fuse: check return value of fuse_simple_request

On 2020-01-20 16:39, Miklos Szeredi wrote:
> On Mon, Jan 20, 2020 at 1:13 PM Cengiz Can <cengiz@...nel.wtf> wrote:
>> 
>> In `fs/fuse/file.c` `fuse_simple_request` is used in multiple places,
>> with its return value properly checked for possible errors.
>> 
>> However the usage on `fuse_file_put` ignores its return value. And the
>> following `fuse_release_end` call used hard-coded error value of `0`.
>> 
>> This triggers a warning in static analyzers and such.
>> 
>> I've added a variable to capture `fuse_simple_request` result and 
>> passed
>> that to `fuse_release_end` instead.
> 
> Which then goes on to ignore the error, so we are exactly where we
> were with some added obscurity, which will be noticed by the next
> generation of static analyzer, when you'd come up with an even more
> obscure way to ignore the error, etc...  This leads to nowhere.

I got your point. Thanks for explaining.

> If this matters (not sure) then we'll need a notation to ignore the
> return value.  Does casting to (void) work?

It should probably work for the sake of silencing the analyzer but I 
think
it would be easier to just ignore the warning and mark is as 
unimportant.

IMHO code should be as readable as possible. So not point in casting it.

If `fuse_simple_request` errors are very rare, we can ignore this patch.

Thank you

> 
> Thanks,
> Miklos

-- 
Cengiz Can
@cengiz_io