From: Manfred Spraul <manfred@colorfullife.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: pinotj@club-internet.fr, nathans@sgi.com, akpm@osdl.org,
linux-kernel@vger.kernel.org
Subject: Re: [Oops] i386 mm/slab.c (cache_flusharray)
Date: Thu, 04 Dec 2003 20:19:53 +0100 [thread overview]
Message-ID: <3FCF88D9.7080002@colorfullife.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0312041035530.6638@home.osdl.org>
[-- Attachment #1: Type: text/plain, Size: 1224 bytes --]
Linus Torvalds wrote:
>Manfred, any ideas? What's different between 2.6.x and 2.4.x in slab?
>
>But it may also be that the bug is in some slab user - since my slab-
>translates-to-page-alloc hack always calls the slab constructor function
>on every allocation, and the destructor gets called immediately after the
>free, my debug version might hide some usage bugs.
>
>
The changes between 2.4 and 2.6 are huge, for both debug and non-debug.
Slab with debugging enabled now calls the destructors/constructor on
every alloc. If page debugging is enabled, then all objects larger than
128 bytes get their own page and are unmapped after kmem_cache_free().
The bio structure is smaller than 128 bytes - that probably explains why
slab didn't catch the oopses that were mentioned in the other thread.
Perhaps something like the attached patch could help to trigger the
oops: It increase the size of the bio structures, then they are handled
by slab debugging.
If it oopses, then call ptrinfo() from the trap handler - it prints the
name of the cache and the caller of the last slab operation. And hexdump
the object (after ptrinfo mapped it), it contains a backtrace from the
kmem_cache_free call.
--
Manfred
[-- Attachment #2: patch-bio --]
[-- Type: text/plain, Size: 690 bytes --]
--- 2.6/fs/bio.c 2003-10-25 20:43:54.000000000 +0200
+++ build-2.6/fs/bio.c 2003-12-04 20:13:52.000000000 +0100
@@ -798,7 +798,7 @@
size = bp->nr_vecs * sizeof(struct bio_vec);
- bp->slab = kmem_cache_create(bp->name, size, 0,
+ bp->slab = kmem_cache_create(bp->name, max(128,size), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!bp->slab)
panic("biovec: can't init slab cache\n");
@@ -815,7 +815,7 @@
static int __init init_bio(void)
{
- bio_slab = kmem_cache_create("bio", sizeof(struct bio), 0,
+ bio_slab = kmem_cache_create("bio", max(128U,sizeof(struct bio)), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!bio_slab)
panic("bio: can't create slab cache\n");
next prev parent reply other threads:[~2003-12-04 19:20 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-04 18:27 [Oops] i386 mm/slab.c (cache_flusharray) pinotj
2003-12-04 18:49 ` Linus Torvalds
2003-12-04 19:09 ` Linus Torvalds
2003-12-04 21:21 ` Nathan Scott
2003-12-05 7:14 ` Christoph Hellwig
2003-12-05 9:34 ` Nathan Scott
2003-12-05 14:22 ` Christoph Hellwig
2003-12-05 3:00 ` Nathan Scott
2003-12-05 6:40 ` Linus Torvalds
2003-12-04 19:19 ` Manfred Spraul [this message]
2003-12-04 21:26 ` Nathan Scott
-- strict thread matches above, loose matches on Subject: below --
2003-12-09 0:57 pinotj
2003-12-09 2:03 ` Nathan Scott
2003-12-09 7:21 ` Christoph Hellwig
2003-12-09 23:58 ` Nathan Scott
2003-12-12 19:00 ` Christoph Hellwig
2003-12-12 20:07 ` Manfred Spraul
2003-12-03 23:06 pinotj
2003-12-03 23:26 ` Linus Torvalds
2003-11-29 17:41 pinotj
2003-12-02 0:36 ` Linus Torvalds
2003-12-02 1:37 ` Nathan Scott
2003-12-02 6:44 ` Nathan Scott
2003-12-02 18:05 ` Mike Fedyk
2003-12-02 20:05 ` Nathan Scott
2003-11-27 18:42 pinotj
2003-11-27 18:55 ` Manfred Spraul
2003-12-02 1:03 ` Mike Fedyk
2003-11-25 17:30 pinotj
2003-11-25 22:51 ` Linus Torvalds
2003-11-27 18:07 ` Manfred Spraul
2003-11-22 7:47 Re: " pinotj
2003-11-22 10:55 ` Manfred Spraul
2003-11-21 18:12 pinotj
2003-11-21 18:58 ` Manfred Spraul
2003-11-20 1:50 pinotj
2003-11-20 2:09 ` Andrew Morton
2003-11-19 18:19 pinotj
2003-11-20 1:07 ` Andrew Morton
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