From: "Vegard Nossum" <vegard.nossum@gmail•com>
To: Greg KH <gregkh@suse•de>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland•pl>,
Dave Hansen <haveblue@us•ibm.com>,
Stephen Rothwell <sfr@canb•auug.org.au>,
kernel-testers@vger•kernel.org, linux-next@vger•kernel.org,
LKML <linux-kernel@vger•kernel.org>,
Pekka Enberg <penberg@cs•helsinki.fi>
Subject: Re: linux-next: Tree for July 18: warning at kernel/lockdep.c:2068 trace_hardirqs_on_caller
Date: Sun, 20 Jul 2008 00:27:26 +0200 [thread overview]
Message-ID: <19f34abd0807191527u61c5ed61kffe2279c8d46915d@mail.gmail.com> (raw)
In-Reply-To: <20080719221723.GB5578@suse.de>
On Sun, Jul 20, 2008 at 12:17 AM, Greg KH <gregkh@suse•de> wrote:
> On Sat, Jul 19, 2008 at 02:59:12PM +0200, Vegard Nossum wrote:
>> On Sat, Jul 19, 2008 at 11:55 AM, Vegard Nossum <vegard.nossum@gmail•com> wrote:
>> > What I don't get here is how SLUB can be used this early in the boot
>> > process. Notice that this is still miles away from the
>> >
>> > SLUB: Genslabs=12, HWalign=128, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
>> >
>> > line, which comes much later. And that kobject_init() _is_ calling
>> > kzalloc() via verify_dynamic_kobject_allocation(). Isn't this an
>> > error?
>> >
>> > (Unfortunately, my "git log" doesn't turn up any recent changes for
>> > any of the affected code paths here.)
>>
>> Ehe... and this is the reason why: The code was added by this patch:
>>
>> commit 0e3638d1e04040121af00195f7e4628078246489
>> Author: Dave Hansen <haveblue@us•ibm.com>
>> Date: Thu Mar 16 17:30:16 2006 -0800
>>
>> warn when statically-allocated kobjects are used
>>
>> ..which only exists in -next. Is that just a truly ancient patch, or
>> did somebody forget to adjust their clock?
>
> It is truely a very old patch, that only lives in my tree, and currently
> isn't planned to go to Linus any year soon.
>
> But it has a very long history of living in the -mm tree, and finding
> real bugs, it's just not "safe" enough to go to Linus's tree. Unless
> you think it is?
Hm. In this case, the patch is not even reporting a problem, it is in
fact in error itself.
The problem is that it calls kzalloc() before the slab caches have
been set up. (Yes, it's a wonder that nothing crashed.) I can only
suggest the addendum
if (!slab_is_available())
return;
Vegard
--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
next prev parent reply other threads:[~2008-07-19 22:27 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-18 9:53 linux-next: Tree for July 18 Stephen Rothwell
2008-07-19 7:28 ` linux-next: Tree for July 18: warning at kernel/lockdep.c:2068 trace_hardirqs_on_caller Mariusz Kozlowski
2008-07-19 9:55 ` Vegard Nossum
[not found] ` <19f34abd0807190255x304173d4wf2bfabb2d5bce511-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-07-19 12:56 ` Pekka Enberg
2008-07-19 12:59 ` Vegard Nossum
[not found] ` <19f34abd0807190559y2fe5ebf9h7095793e82de3122-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-07-19 13:22 ` Stephen Rothwell
2008-07-19 22:17 ` Greg KH
2008-07-19 22:27 ` Vegard Nossum [this message]
[not found] ` <19f34abd0807191527u61c5ed61kffe2279c8d46915d-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-07-19 22:41 ` Greg KH
2008-07-19 22:44 ` Vegard Nossum
[not found] ` <19f34abd0807191544nfd73be5nf7dde4b61992a7e8-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-07-19 22:58 ` Greg KH
2008-07-19 23:11 ` Vegard Nossum
[not found] ` <19f34abd0807191611y7cabf405iad307ba79591e04f-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-07-19 23:20 ` Greg KH
2008-07-20 12:51 ` Bernhard Walle
2008-07-20 9:01 ` Dave Hansen
2008-07-20 9:35 ` Thomas Meyer
2008-07-20 13:03 ` Bernhard Walle
[not found] ` <20080720150341.7cd381c2-Hxm9IJOWyO+kWa+peg0mPg@public.gmane.org>
2008-07-20 15:44 ` Bernhard Walle
2008-07-21 13:17 ` Vivek Goyal
[not found] ` <20080721131721.GB4451-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-07-21 13:25 ` Bernhard Walle
2008-07-21 13:39 ` Vivek Goyal
[not found] ` <20080721133937.GC4451-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-07-21 15:00 ` Bernhard Walle
[not found] ` <20080721170037.1a0046b1-oJhqVyG5NZ9bpigZmTR7Iw@public.gmane.org>
2008-07-22 6:15 ` Yasunori Goto
2008-07-20 12:48 ` Bernhard Walle
[not found] ` <20080718195352.e562a00f.sfr-3FnU+UHB4dNDw9hX6IcOSA@public.gmane.org>
2008-07-19 7:39 ` linux-next: Tree for July 18: nfs problems Mariusz Kozlowski
2008-07-19 9:35 ` linux-next: Tree for July 18: powerpc g3 hangs Mariusz Kozlowski
2008-07-19 15:31 ` linux-next: Tree for July 18 (very early crash on x86_32) Bartlomiej Zolnierkiewicz
2008-07-20 0:20 ` linux-next: Tree for July 18: sky2 WOL broken Rafael J. Wysocki
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