From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42150) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBfkM-0007jr-Pl for qemu-devel@nongnu.org; Tue, 29 Nov 2016 05:34:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cBfkK-00072k-HD for qemu-devel@nongnu.org; Tue, 29 Nov 2016 05:34:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39162) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cBfkK-00072M-Bq for qemu-devel@nongnu.org; Tue, 29 Nov 2016 05:34:44 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1F9FE61B91 for ; Tue, 29 Nov 2016 10:34:43 +0000 (UTC) From: Fam Zheng Date: Tue, 29 Nov 2016 18:34:38 +0800 Message-Id: <20161129103438.15955-2-famz@redhat.com> In-Reply-To: <20161129103438.15955-1-famz@redhat.com> References: <20161129103438.15955-1-famz@redhat.com> Subject: [Qemu-devel] [PULL 1/1] hbitmap: Fix shifts of constants by granularity List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: stefanha@redhat.com From: Max Reitz An hbitmap's granularity may be anything from 0 to 63, so when shifting constants by its value, they should not be plain ints. Even having changed the types, hbitmap_serialization_granularity() still tries to shift 64 to the right by the granularity. This operation is undefined if the granularity is greater than 57. Adding an assertion is fine for now, because serializing is done only in tests so far, but this means that only bitmaps with a granularity below 58 can be serialized and we should thus add a hbitmap_is_serializable() function later. One of the two places touched in this patch uses QEMU_ALIGN_UP(x, 1 << y). We can use ROUND_UP() there, since the second parameter is obviously a power of two. Signed-off-by: Max Reitz Message-Id: <20161115224732.1334-1-mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi Signed-off-by: Fam Zheng --- util/hbitmap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/util/hbitmap.c b/util/hbitmap.c index 5d1a21c..9f691b7 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -399,9 +399,13 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item) uint64_t hbitmap_serialization_granularity(const HBitmap *hb) { + /* Must hold true so that the shift below is defined + * (ld(64) == 6, i.e. 1 << 6 == 64) */ + assert(hb->granularity < 64 - 6); + /* Require at least 64 bit granularity to be safe on both 64 bit and 32 bit * hosts. */ - return 64 << hb->granularity; + return UINT64_C(64) << hb->granularity; } /* Start should be aligned to serialization granularity, chunk size should be @@ -594,7 +598,7 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size) if (shrink) { /* Don't clear partial granularity groups; * start at the first full one. */ - uint64_t start = QEMU_ALIGN_UP(num_elements, 1 << hb->granularity); + uint64_t start = ROUND_UP(num_elements, UINT64_C(1) << hb->granularity); uint64_t fix_count = (hb->size << hb->granularity) - start; assert(fix_count); -- 2.9.3