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| author | Zhang Yanfei <zhangyanfei.yes@gmail.com> | 2013-07-08 16:00:19 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-09 10:33:23 -0700 |
| commit | bcb615a81b1765864c71c50afb56631e7a1e5283 (patch) | |
| tree | 216f4970befea4f21394fc76e9b55cf15424c678 /mm/vmalloc.c | |
| parent | 64363aad5ff1b878230e91223038c26a2205bff3 (diff) | |
| download | lwn-bcb615a81b1765864c71c50afb56631e7a1e5283.tar.gz lwn-bcb615a81b1765864c71c50afb56631e7a1e5283.zip | |
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>
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 6 |
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)) |