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| author | David Rientjes <rientjes@google.com> | 2009-09-21 17:04:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:47 -0700 |
| commit | 19da3dd157f8db6fe727ff268dab4791d55a6371 (patch) | |
| tree | 4259074638b384e765c73542d74dd8f44750068b /include/linux/poison.h | |
| parent | e6de3988aa52debb25a427d085061f3bf1181d54 (diff) | |
| download | lwn-19da3dd157f8db6fe727ff268dab4791d55a6371.tar.gz lwn-19da3dd157f8db6fe727ff268dab4791d55a6371.zip | |
flex_array: poison free elements
Newly initialized flex_array's and/or flex_array_part's are now poisoned
with a new poison value, FLEX_ARRAY_FREE. It's value is similar to
POISON_FREE used in the various slab allocators, but is different to
distinguish between flex array's poisoned kmem and slab allocator poisoned
kmem.
This will allow us to identify flex_array_part's that only contain free
elements (and free them with an addition to the flex_array API). This
could also be extended in the future to identify `get' uses on elements
that have not been `put'.
If __GFP_ZERO is passed for a part's gfp mask, the poisoning is avoided.
These elements are considered to be in-use since they have been
initialized.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/poison.h')
| -rw-r--r-- | include/linux/poison.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 6729f7dcd60e..7fc194aef8c2 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -65,6 +65,9 @@ #define MUTEX_DEBUG_INIT 0x11 #define MUTEX_DEBUG_FREE 0x22 +/********** lib/flex_array.c **********/ +#define FLEX_ARRAY_FREE 0x6c /* for use-after-free poisoning */ + /********** security/ **********/ #define KEY_DESTROY 0xbd |