Fix bitmap_scnlistprintf for empty masks

When a bitmap is empty bitmap_scnlistprintf() would leave the buffer
uninitialized.  Set it to an empty string in this case.

I didn't see any in normal kernel callers hitting this, but some custom
debug code of mine did.

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 26ebafa..2c9242e 100644 (file)
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -469,6 +469,10 @@ int bitmap_scnlistprintf(char *buf, unsigned int buflen,
        /* current bit is 'cur', most recently seen range is [rbot, rtop] */
        int cur, rbot, rtop;
 
+       if (buflen == 0)
+               return 0;
+       buf[0] = 0;
+
        rbot = cur = find_first_bit(maskp, nmaskbits);
        while (cur < nmaskbits) {
                rtop = cur;