This is a note to let you know that I've just added the patch titled
mm: fix wrong vmap address calculations with odd NR_CPUS values
to the 2.6.32-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.32.git;a=summary
The filename of the patch is:
mm-fix-wrong-vmap-address-calculations-with-odd-nr_cpus.patch
and it can be found in the queue-2.6.32 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.32 longterm
tree,
please let <[email protected]> know about it.
>From f982f91516fa4cfd9d20518833cd04ad714585be Mon Sep 17 00:00:00 2001
From: Clemens Ladisch <[email protected]>
Date: Tue, 21 Jun 2011 22:09:50 +0200
Subject: mm: fix wrong vmap address calculations with odd NR_CPUS values
From: Clemens Ladisch <[email protected]>
commit f982f91516fa4cfd9d20518833cd04ad714585be upstream.
Commit db64fe02258f ("mm: rewrite vmap layer") introduced code that does
address calculations under the assumption that VMAP_BLOCK_SIZE is a
power of two. However, this might not be true if CONFIG_NR_CPUS is not
set to a power of two.
Wrong vmap_block index/offset values could lead to memory corruption.
However, this has never been observed in practice (or never been
diagnosed correctly); what caught this was the BUG_ON in vb_alloc() that
checks for inconsistent vmap_block indices.
To fix this, ensure that VMAP_BLOCK_SIZE always is a power of two.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=31572
Reported-by: Pavel Kysilka <[email protected]>
Reported-by: Matias A. Fonzo <[email protected]>
Signed-off-by: Clemens Ladisch <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: Krzysztof Helt <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/vmalloc.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -671,9 +671,10 @@ static void free_unmap_vmap_area_addr(un
#define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
#define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
#define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
-#define VMAP_BBMAP_BITS VMAP_MIN(VMAP_BBMAP_BITS_MAX,
\
- VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
- VMALLOC_PAGES / NR_CPUS / 16))
+#define VMAP_BBMAP_BITS \
+ VMAP_MIN(VMAP_BBMAP_BITS_MAX, \
+ VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
+ VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
Patches currently in longterm-queue-2.6.32 which might be from
[email protected] are
/home/gregkh/linux/longterm/longterm-queue-2.6.32/queue-2.6.32/mm-fix-wrong-vmap-address-calculations-with-odd-nr_cpus.patch
_______________________________________________
stable mailing list
[email protected]
http://linux.kernel.org/mailman/listinfo/stable
