Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota

From	David Herrmann <dh.herrmann@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota
Date	2015-07-05 11:10 +0200
Message-ID	<pIO5Z-W8-29@gated-at.bofh.it> (permalink)
References	(1 earlier) <pGkOK-5Cy-5@gated-at.bofh.it> <pHIvE-qX-5@gated-at.bofh.it> <pHN2i-3lz-17@gated-at.bofh.it> <pHNvl-3Pj-35@gated-at.bofh.it> <pHQMx-5Ls-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi

On Thu, Jul 2, 2015 at 7:47 PM, Sergei Zviagintsev <sergei@s15v.net> wrote:
> Hi Djalal,
>
> On Thu, Jul 02, 2015 at 03:13:41PM +0100, Djalal Harouni wrote:
> [...]
>> > My journey with this piece of code began from spotting and immediately
>> > "fixing" the overflow issue :) Then I decided to dig into the
>> > out-of-tree repo to find the origin of this line. What I found were
>> > commits af8e2f750985 and ac5c385cc67a in which Djalal "fixed" it as
>> > well, but then reverted back to the original code.
>> >
>> > Surely we can drop this explanation, but if one of kdbus maintainers
>> > experienced difficulties in understanding this piece of code, wouldn't
>> > one who sees this code in the first time have the same issues?
>> Yes there was lot of work in this area to make sure that the quota
>> accounting is correct! the previous commits the one that tried to clean
>> things up and the revert were both correct :-) ,
>
> I cannot agree that commit af8e2f750985 in out-of-tree repo was correct.

Exactly, that's why the commit got reverted. The U32_MAX check is
*not* about overflows of pool-memory, but rather about overflows in
quota-accounting.

Thanks
David
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Thread

Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota David Herrmann <dh.herrmann@gmail.com> - 2015-07-02 11:00 +0200
  Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota Sergei Zviagintsev <sergei@s15v.net> - 2015-07-02 15:50 +0200
    Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota Djalal Harouni <tixxdz@opendz.org> - 2015-07-02 16:20 +0200
      Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota David Herrmann <dh.herrmann@gmail.com> - 2015-07-05 11:10 +0200
    Re: [PATCH RFC 5/5] kdbus: improve tests on incrementing quota Sergei Zviagintsev <sergei@s15v.net> - 2015-07-05 10:30 +0200

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