linux-kernel - Re: [PATCH v2] drm/amdkfd: Fix memory leaks according to error branches

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.22.394.2006201126130.2918@hadrien>
Date:   Sat, 20 Jun 2020 11:37:19 +0200 (CEST)
From:   Julia Lawall <julia.lawall@...ia.fr>
To:     Markus Elfring <Markus.Elfring@....de>
cc:     Bernard Zhao <bernard@...o.com>, opensource.kernel@...o.com,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        Felix Kühling <Felix.Kuehling@....com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>
Subject: Re: [PATCH v2] drm/amdkfd: Fix memory leaks according to error
 branches

On Sat, 20 Jun 2020, Markus Elfring wrote:

> > The function kobject_init_and_add alloc memory like:
> > kobject_init_and_add->kobject_add_varg->kobject_set_name_vargs
> > ->kvasprintf_const->kstrdup_const->kstrdup->kmalloc_track_caller
> > ->kmalloc_slab, in err branch this memory not free. If use
> > kmemleak, this path maybe catched.
> > These changes are to add kobject_put in kobject_init_and_add
> > failed branch, fix potential memleak.
>
> I suggest to improve this change description.
>
> * Can an other wording variant be nicer?

Markus's suggestion is as usual extremely imprecise.  However, I also find
the message quite unclear.

It would be good to always use English words.  alloc and err are not
English words.  Perhaps most people will figure out what they are
abbreviations for, but it would be better to use a few more letters to
make it so that no one has to guess.

Then there are a bunch of things that are connected by arrows with no
spaces between them.  The most obvious meaning of an arrow with no space
around it is a variable dereference.  After spending some mental effort,
one can realize that that is not what you mean here.  A layout like:

   first_function ->
     second_function ->
       third_function

would be much more readable.

I don't know what "this patch maybe catched" means.  Is "catched" supposed
to be "caught" or "cached"?  Overall, the sentence could be "Kmemleak
could possibly detect this issue", or something like that.  But I don't
know what this means.  Did you detect the problem with kmemleak?  if you
did not detect the problem with kmemleak, and overall you don't know
whether kmemleak would detect the bug or not, is this information useful
at all for the patch?

"These changes are to" makes a lot of words with no information.  While it
is perhaps not necessary to slavishly follow the rule about using the
imperative, if it is convenient to use the imperative, doing so eliminates
such meaningless phrases.

memleak is also not an English word.  Memory leak is only a few more
characters, and doesn't require the reader to make the small extra effort
to figure out what you mean.

julia

>
> * Will the tag “Fixes” become helpful for the commit message?
>
> Regards,
> Markus
>