From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33521) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUFof-0003mW-Vo for qemu-devel@nongnu.org; Thu, 19 Jan 2017 11:44:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cUFob-0004Kc-0A for qemu-devel@nongnu.org; Thu, 19 Jan 2017 11:44:02 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:34979 helo=mx01.kamp.de) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cUFoa-0004Am-Nl for qemu-devel@nongnu.org; Thu, 19 Jan 2017 11:43:56 -0500 From: Peter Lieven Date: Thu, 19 Jan 2017 17:43:50 +0100 Message-Id: <1484844230-24490-1-git-send-email-pl@kamp.de> Subject: [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: qemu-devel@nongnu.org Cc: famz@redhat.com, pbonzini@redhat.com, Peter Lieven 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); -- 1.9.1