[PATCH] fix broken lib/genalloc.c

genalloc improperly stores the sizes of freed chunks, allocates overlapping
memory regions, and oopses after its in-band data is overwritten.

Signed-off-by: Chris Humbert <mahadri-kernel@drigon.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/lib/genalloc.c b/lib/genalloc.c
index d6d30d2e7166..9ce0a6a3b85a 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -95,12 +95,10 @@ unsigned long gen_pool_alloc(struct gen_pool *poolp, int size)
         if (size > max_chunk_size)
                 return 0;
 
-        i = 0;
-
         size = max(size, 1 << ALLOC_MIN_SHIFT);
-        s = roundup_pow_of_two(size);
-
-        j = i;
+        i = fls(size - 1);
+        s = 1 << i;
+        j = i -= ALLOC_MIN_SHIFT;
 
         spin_lock_irqsave(&poolp->lock, flags);
         while (!h[j].next) {
@@ -153,10 +151,10 @@ void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size)
         if (size > max_chunk_size)
                 return;
 
-        i = 0;
-
         size = max(size, 1 << ALLOC_MIN_SHIFT);
-        s = roundup_pow_of_two(size);
+        i = fls(size - 1);
+        s = 1 << i;
+        i -= ALLOC_MIN_SHIFT;
 
         a = ptr;