linux-kernel - Re: [PULL] param sysfs oops (simple, leaky) fix, bool arrays fix

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Date:	Wed, 05 May 2010 10:25:14 +0300
From:	Artem Bityutskiy <dedekind1@...il.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Takashi Iwai <tiwai@...e.de>,
	Sitsofe Wheeler <sitsofe@...oo.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Christof Schmitt <christof.schmitt@...ibm.com>
Subject: Re: [PULL] param sysfs oops (simple, leaky) fix, bool arrays fix

On Wed, 2010-05-05 at 15:03 +0930, Rusty Russell wrote:
> On Wed, 5 May 2010 03:37:19 am Artem Bityutskiy wrote:
> > On Tue, 2010-05-04 at 11:53 +0930, Rusty Russell wrote:
> > > On Tue, 27 Apr 2010 08:23:24 pm Artem Bityutskiy wrote:
> > > > Rusty, correct me if I'm wrong, but it looks like the above memleak was
> > > > introduced by e180a6b7759a99a28cbcce3547c4c80822cb6c2a, where you added
> > > > the kstrdup(). So you kinda fixed the sysfs case (it still memleaks
> > > > though), but at the cost of additional insmod/rmmod leak, right?
> > > 
> > > Yep!
> > 
> > Are you working/planning to work on fixing this regression?
> 
> I'm still ambivalent on it; I have patches but it's a lot of churn for not
> much gain.
> 
> To fix this, we need a way to lock parameters against changing by sysfs, and
> we need to use it everywhere.  Past experience has demonstrated that this will
> never be maintained.  
> 
> On the other hand, the leak is trivial.

Well, I am not very concerned with the "changing by sysfs" leak. This is
not a big deal, IMHO. I am concerned with the "rmmod" leak, which did
not exist before your patches, but exists now. People may do a lot of
insmod/rmmod, and on each rmmod they will loose this kstrdup-ed string. 

I'll take a look at this tree, thank you.

> Here's a git tree if you want to look further:
> 
> The following changes since commit 05ce7bfe547c9fa967d9cab6c37867a9cb6fb3fa:
>   Linus Torvalds (1):
>         Merge branch 'for_linus' of git://git.kernel.org/.../jack/linux-fs-2.6
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/rusty/linux-2.6-param-fixes.git master

Just in case others will clone, the correct URL seems to be

git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-param-fixes.git master

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

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