From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38330) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUYDE-00031g-6O for qemu-devel@nongnu.org; Fri, 20 Jan 2017 07:22:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cUYDB-0003UD-3j for qemu-devel@nongnu.org; Fri, 20 Jan 2017 07:22:36 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43746) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cUYDA-0003Ts-To for qemu-devel@nongnu.org; Fri, 20 Jan 2017 07:22:33 -0500 References: <1484844230-24490-1-git-send-email-pl@kamp.de> From: Paolo Bonzini Message-ID: Date: Fri, 20 Jan 2017 13:22:29 +0100 MIME-Version: 1.0 In-Reply-To: <1484844230-24490-1-git-send-email-pl@kamp.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] bitmap: assert that start and nr are non negative List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven , qemu-devel@nongnu.org Cc: famz@redhat.com On 19/01/2017 17:43, Peter Lieven wrote: > commit e1123a3b introduced a data corruption regression > in the iscsi driver because it passed -1 as nr to bitmap_set > and bitmap_clear. Add an assertion to catch such flaws earlier. > > Suggested-by: Fam Zheng > Signed-off-by: Peter Lieven > --- > util/bitmap.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/util/bitmap.c b/util/bitmap.c > index 43ed011..c1a84ca 100644 > --- a/util/bitmap.c > +++ b/util/bitmap.c > @@ -164,6 +164,8 @@ void bitmap_set(unsigned long *map, long start, long nr) > int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); > unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); > > + assert(start >= 0 && nr >= 0); > + > while (nr - bits_to_set >= 0) { > *p |= mask_to_set; > nr -= bits_to_set; > @@ -184,6 +186,8 @@ void bitmap_set_atomic(unsigned long *map, long start, long nr) > int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); > unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); > > + assert(start >= 0 && nr >= 0); > + > /* First word */ > if (nr - bits_to_set > 0) { > atomic_or(p, mask_to_set); > @@ -221,6 +225,8 @@ void bitmap_clear(unsigned long *map, long start, long nr) > int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); > unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); > > + assert(start >= 0 && nr >= 0); > + > while (nr - bits_to_clear >= 0) { > *p &= ~mask_to_clear; > nr -= bits_to_clear; > @@ -243,6 +249,8 @@ bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr) > unsigned long dirty = 0; > unsigned long old_bits; > > + assert(start >= 0 && nr >= 0); > + > /* First word */ > if (nr - bits_to_clear > 0) { > old_bits = atomic_fetch_and(p, ~mask_to_clear); > Queued, thanks. Paolo