Subject: + mm-vmallocc-fix-an-overflow-bug-in-alloc_vmap_area.patch added to -mm tree
To: zhangyanfei.yes@xxxxxxxxx,dbaluta@xxxxxxxxxxx,kosaki.motohiro@xxxxxxxxxxxxxx,minchan@xxxxxxxxxx,rientjes@xxxxxxxxxx,unix140@xxxxxxxxx,zhangyanfei@xxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 25 Jun 2013 15:42:59 -0700
The patch titled
Subject: mm/vmalloc.c: fix an overflow bug in alloc_vmap_area()
has been added to the -mm tree. Its filename is
mm-vmallocc-fix-an-overflow-bug-in-alloc_vmap_area.patch
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From: Zhang Yanfei <zhangyanfei.yes@xxxxxxxxx>
Subject: mm/vmalloc.c: fix an overflow bug in alloc_vmap_area()
When searching a vmap area in the vmalloc space, we use (addr + size - 1)
to check if the value is less than addr, which is an overflow. But we
assign (addr + size) to vmap_area->va_end.
So if we come across the below case:
(addr + size - 1) : not overflow
(addr + size) : overflow
we will assign an overflow value (e.g 0) to vmap_area->va_end, And this
will trigger BUG in __insert_vmap_area, causing system panic.
So using (addr + size) to check the overflow should be the correct
behaviour, not (addr + size - 1).
Signed-off-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
Reported-by: Ghennadi Procopciuc <unix140@xxxxxxxxx>
Tested-by: Daniel Baluta <dbaluta@xxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff -puN mm/vmalloc.c~mm-vmallocc-fix-an-overflow-bug-in-alloc_vmap_area mm/vmalloc.c
--- a/mm/vmalloc.c~mm-vmallocc-fix-an-overflow-bug-in-alloc_vmap_area
+++ a/mm/vmalloc.c
@@ -388,12 +388,12 @@ nocache:
addr = ALIGN(first->va_end, align);
if (addr < vstart)
goto nocache;
- if (addr + size - 1 < addr)
+ if (addr + size < addr)
goto overflow;
} else {
addr = ALIGN(vstart, align);
- if (addr + size - 1 < addr)
+ if (addr + size < addr)
goto overflow;
n = vmap_area_root.rb_node;
@@ -420,7 +420,7 @@ nocache:
if (addr + cached_hole_size < first->va_start)
cached_hole_size = first->va_start - addr;
addr = ALIGN(first->va_end, align);
- if (addr + size - 1 < addr)
+ if (addr + size < addr)
goto overflow;
if (list_is_last(&first->list, &vmap_area_list))
_
Patches currently in -mm which might be from zhangyanfei.yes@xxxxxxxxx are
mm-vmallocc-fix-an-overflow-bug-in-alloc_vmap_area.patch
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