Re: [ 07/48] mm: fix slab->page _count corruption when using slub
From: Herton Ronaldo Krzesinski <hidden>
Date: 2012-07-02 23:46:22
Also in:
lkml
On Sun, Jul 01, 2012 at 06:20:13PM +0100, Ben Hutchings wrote:
3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pravin B Shelar <redacted> commit abca7c4965845924f65d40e0aa1092bdd895e314 upstream. On arches that do not support this_cpu_cmpxchg_double() slab_lock is used to do atomic cmpxchg() on double word which contains page->_count. The page count can be changed from get_page() or put_page() without taking slab_lock. That corrupts page counter. Fix it by moving page->_count out of cmpxchg_double data. So that slub does no change it while updating slub meta-data in struct page.
Hi, I got a frozen machine on boot with 3.2.22 proposed patches, bisect pointed out to this commit (and reverting only this commit on top of 3.2.22 patches confirmed it). So far I was able to reproduce always. Only happened with an x86_64 kernel, gzipped config attached. Using earlyprintk=vga, I'm able to see the boot process is stuck just right after "Memory: ...k available..." message (right before SLUB prints its initialization message).
quoted hunk ↗ jump to hunk
[akpm@linux-foundation.org: use standard comment layout, tweak comment text] Reported-by: Amey Bhide <redacted> Signed-off-by: Pravin B Shelar <redacted> Acked-by: Christoph Lameter <redacted> Cc: Pekka Enberg <redacted> Cc: Andrea Arcangeli <redacted> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <redacted> --- include/linux/mm_types.h | 10 ++++++++++ 1 file changed, 10 insertions(+)diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index dad95bd..704a626 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h@@ -57,8 +57,18 @@ struct page { }; union { +#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ + defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) /* Used for cmpxchg_double in slub */ unsigned long counters; +#else + /* + * Keep _count separate from slub cmpxchg_double data. + * As the rest of the double word is protected by + * slab_lock but _count is not. + */ + unsigned counters; +#endif struct { --To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
-- []'s Herton
Attachments
- config-3.2.21-030221-generic.gz [application/octet-stream] 35281 bytes