[PATCH] isofs buffer management fix

There's a double-free in the isofs filesystem.

Invalidate this pointer so it doesn't get freed twice.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/isofs/rock.c

@@ -62,7 +62,7 @@
 }                                     
 
 #define MAYBE_CONTINUE(LABEL,DEV) \
-  {if (buffer) kfree(buffer); \
+  {if (buffer) { kfree(buffer); buffer = NULL; } \
   if (cont_extent){ \
     int block, offset, offset1; \
     struct buffer_head * pbh; \