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From: Christoph Lameter <cl@linux.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: glommer@parallels.com, penberg@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [linux-next-20130422] Bug in SLAB?
Date: Tue, 30 Apr 2013 17:27:53 +0000	[thread overview]
Message-ID: <0000013e5bfc7c4d-54fa9464-dccd-4157-b4a5-22594261eaf3-000000@email.amazonses.com> (raw)
In-Reply-To: <201305010101.CGB86424.JFQOtSFOVOLFHM@I-love.SAKURA.ne.jp>


On Wed, 1 May 2013, Tetsuo Handa wrote:

> Christoph Lameter wrote:
> > On Tue, 30 Apr 2013, Tetsuo Handa wrote:
> >
> > > The testcases still trigger BUG() at 32M:
> >
> > I thought we established that MAX_ORDER only allows a maximum of 8M sized
> > allocations? Why are you trying 32M?
>
> Only for regression testing. At least until Linux 3.9, requesting too large
> size didn't trigger oops, did it? I'm not expecting kmalloc() to trigger oops
> for Linux 3.10 and future kernels.

It did for SLUB. SLAB returned NULL for some cases.

> "kmalloc() returning NULL for these allocations" is needed by "try kmalloc()
> first, fallback to vmalloc()" allocation. There are kernel modules which expect
> kmalloc() to return NULL rather than oops when the requested size is larger
> than KMALLOC_MAX_SIZE bytes. If kmalloc() suddenly starts triggering oops, such
> modules will break.

This behavior has been in there for years. Why try a kmalloc that
always fails since the size is too big?

> Anyway, there is a regression we want to fix : we won't be able to boot
> Linux 3.10-rc1 for x86_32 built with CONFIG_DEBUG_SLAB=y &&
> CONFIG_DEBUG_SPINLOCK=y && CONFIG_DEBUG_PAGEALLOC=y .
> ("Fix off by one error in slab.h" did not fix the regression.)

Hmm... Where does this fail? In slab?



  reply	other threads:[~2013-04-30 17:27 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-24 12:08 [linux-next-20130422] Bug in bootup code or debug code? Tetsuo Handa
2013-04-25 12:20 ` [linux-next-20130422] Bug in SLAB? Tetsuo Handa
2013-04-29  2:40   ` Tetsuo Handa
2013-04-29 10:12     ` Pekka Enberg
2013-04-29 14:44       ` Glauber Costa
2013-04-29 14:59         ` Christoph Lameter
2013-04-29 15:16           ` Glauber Costa
2013-04-29 15:46             ` Christoph Lameter
2013-04-29 15:54               ` Glauber Costa
2013-04-29 15:28           ` Tetsuo Handa
2013-04-29 16:16             ` Tetsuo Handa
2013-05-09 12:25               ` Tetsuo Handa
2013-05-09 14:14                 ` Christoph Lameter
2013-05-09 21:54                   ` Tetsuo Handa
2013-05-10 12:38                     ` Tetsuo Handa
2013-05-10 15:57                       ` Christoph Lameter
     [not found]                         ` <201305272153.HEH51089.OHFQMOOtFLSFVJ@I-love.SAKURA.ne.jp>
2013-06-17 11:59                           ` Tetsuo Handa
2013-04-29 17:48             ` Christoph Lameter
2013-04-29 21:45               ` Tetsuo Handa
2013-04-30 14:26                 ` Christoph Lameter
2013-04-30 16:01                   ` Tetsuo Handa
2013-04-30 17:27                     ` Christoph Lameter [this message]
2013-05-01  8:05                       ` Pekka Enberg
2013-05-02 15:12                         ` Christoph Lameter
2013-05-01 12:14                       ` Tetsuo Handa
2013-05-02 11:51                         ` Tetsuo Handa
2013-05-02 20:53                         ` Christoph Lameter
2013-05-03  8:26                           ` Tetsuo Handa
2013-05-03 15:43                             ` Christoph Lameter
2013-05-06  6:59                               ` Geert Uytterhoeven
2013-05-06  7:27                                 ` Pekka Enberg
2013-05-03 18:04                             ` Christoph Lameter
2013-05-03 18:48                               ` Tetsuo Handa
2013-05-03 19:21                                 ` Christoph Lameter
2013-05-04  0:15                                   ` Tetsuo Handa
2013-05-06 13:46                                     ` Christoph Lameter
2013-05-07 10:38                                       ` Tetsuo Handa
2013-05-07 14:28                                         ` Christoph Lameter
2013-07-01 20:09                                           ` Andrew Morton
2013-07-01 21:45                                             ` Tetsuo Handa
2013-07-01 21:53                                               ` Andrew Morton
2013-07-02 12:49                                                 ` Tetsuo Handa
2013-07-02 19:12                                                   ` Andrew Morton
2013-07-07 15:58                                                     ` Pekka Enberg
2013-05-06  6:32                               ` Pekka Enberg
2013-05-06 13:47                                 ` Christoph Lameter
2013-05-06 20:24                               ` Pekka Enberg
2013-05-07 14:23                                 ` Christoph Lameter
2013-05-07 14:44                                   ` Pekka Enberg
2013-05-07 15:40                                     ` Christoph Lameter
2013-04-30 14:34                 ` Christoph Lameter
2013-05-01  8:03                   ` Pekka Enberg
2013-05-02 15:13                     ` Christoph Lameter
2013-04-30 15:16                 ` Fix off by one error in slab.h Christoph Lameter
2013-04-29  2:56   ` [linux-next-20130422] Bug in SLAB? Zhan Jianyu
2013-04-29  2:56     ` Zhan Jianyu
2013-04-29  3:56     ` Tetsuo Handa

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