virBitmapNewEmpty() can create a bitmap with 0 lenght. With such a bitmap virBitmapToString will return NULL rather than an empty string. Initialize the buffer to avoid that. Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx> --- src/util/virbitmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/util/virbitmap.c b/src/util/virbitmap.c index fcb8e1101a..f1443c3ecf 100644 --- a/src/util/virbitmap.c +++ b/src/util/virbitmap.c @@ -345,6 +345,9 @@ virBitmapToString(virBitmapPtr bitmap) sz = bitmap->map_len; + /* initialize buffer to return empty string for 0 length bitmap */ + virBufferAdd(&buf, "", -1); + while (sz--) { virBufferAsprintf(&buf, "%0*lx", VIR_BITMAP_BITS_PER_UNIT / 4, -- 2.26.2