linux-kernel - Re: [PATCH v2] coccinelle: api: semantic patch to use pm_runtime_resume_and

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.2.22.394.2104271542170.5173@hadrien>
Date:   Tue, 27 Apr 2021 15:44:25 +0200 (CEST)
From:   Julia Lawall <julia.lawall@...ia.fr>
To:     Johan Hovold <johan@...nel.org>
cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        kernel-janitors@...r.kernel.org,
        Gilles Muller <Gilles.Muller@...ia.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Michal Marek <michal.lkml@...kovi.net>, cocci@...teme.lip6.fr,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] coccinelle: api: semantic patch to use
 pm_runtime_resume_and_get



On Tue, 27 Apr 2021, Johan Hovold wrote:

> On Mon, Apr 26, 2021 at 08:54:04PM +0200, Julia Lawall wrote:
> > pm_runtime_get_sync keeps a reference count on failure, which can lead
> > to leaks.  pm_runtime_resume_and_get drops the reference count in the
> > failure case.  This rule very conservatively follows the definition of
> > pm_runtime_resume_and_get to address the cases where the reference
> > count is unlikely to be needed in the failure case.
> >
> > pm_runtime_resume_and_get was introduced in
> > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to
> > deal with usage counter")
> >
> > Signed-off-by: Julia Lawall <Julia.Lawall@...ia.fr>
>
> As I've said elsewhere, not sure trying to do a mass conversion of this
> is a good idea. People may not be used to the interface, but it is
> consistent and has its use. The recent flurry of conversions show that
> those also risk introducing new bugs in code that is currently tested
> and correct.

I looked some of the patches you commented on, and this rule would not
have transformed those cases.  This rule is very restricted to ensure that
the transformed code follows the behavior of the new function.

>
> By giving the script kiddies another toy like this, the influx of broken
> patches is just bound to increase.
>
> Would also be good to CC the PM maintainer on this issue.

Sure, I can resend with Rafael in CC.

julia