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authorZhang Yanfei <zhangyanfei.yes@gmail.com>2013-07-08 16:00:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 10:33:23 -0700
commitbcb615a81b1765864c71c50afb56631e7a1e5283 (patch)
tree216f4970befea4f21394fc76e9b55cf15424c678
parent64363aad5ff1b878230e91223038c26a2205bff3 (diff)
downloadlinux-linaro-stable-bcb615a81b1765864c71c50afb56631e7a1e5283.tar.gz
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@cn.fujitsu.com> Reported-by: Ghennadi Procopciuc <unix140@gmail.com> Tested-by: Daniel Baluta <dbaluta@ixiacom.com> Cc: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmalloc.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a649186669a3..13a54953a273 100644
--- a/mm/vmalloc.c
+++ b/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))