linux-kernel - Re: [Bug #15589] 2.6.34-rc1: Badness at fs/proc/generic.c:316

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Date:	Wed, 21 Apr 2010 10:25:27 +1000
From:	Michael Ellerman <michael@...erman.id.au>
To:	Christian Kujau <lists@...dbynature.de>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linuxppc-dev@...abs.org, schwab@...ux-m68k.org,
	Kernel Testers List <kernel-testers@...r.kernel.org>,
	adobriyan@...il.com, Maciej Rutecki <maciej.rutecki@...il.com>
Subject: Re: [Bug #15589] 2.6.34-rc1: Badness at fs/proc/generic.c:316

On Tue, 2010-04-20 at 11:15 -0700, Christian Kujau wrote:
> On Tue, 20 Apr 2010 at 22:18, Michael Ellerman wrote:
> > Try this 100% unbuilt, 100% untested patch.
> 
> I added GFP_KERNEL to kstrdup to make the compile error go away:
> 
> fs/proc/proc_devtree.c: In function ‘unslash_name’:
> fs/proc/proc_devtree.c:183: error: too few arguments to function ‘kstrdup’
> make[2]: *** [fs/proc/proc_devtree.o] Error 1
> make[1]: *** [fs/proc] Error 2
> make: *** [fs] Error 2

Yeah oops, told you I hadn't built it.

> And now 2.6.34-rc5 compiles and boots without the warning. Thanks! 
> New dmesg and /proc/device-tree on:
> 
>   http://nerdbynature.de/bits/2.6.34-rc1/xlate_proc_name/

Cool, and we see:

./uni-n@...00000/i2c@...01000/i2c-bus@...an@...pulses_rev

Which is the one that needed fixing.

> Alexey mentioned that this is "wasteful" - does it make the kernel slower? 
> I have not done any performance tests, but I'd rather stick with the 
> warning than make this Powerbook G4 any more slower :-\

Maybe a little. It has to check every string to see if it contains a
"/". But then you save the cost of taking an exeception for the WARN,
which might make up the difference. But it's a one time fixup at boot,
so it's not going to be noticeable.

cheers

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