From nobody Fri Nov 7 12:34:54 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1539106176784582.1981279189743; Tue, 9 Oct 2018 10:29:36 -0700 (PDT) Received: from localhost ([::1]:53068 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9vp9-0007me-P6 for importer@patchew.org; Tue, 09 Oct 2018 13:29:35 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46579) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9vkr-0004di-3B for qemu-devel@nongnu.org; Tue, 09 Oct 2018 13:25:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g9vkq-00055g-9a for qemu-devel@nongnu.org; Tue, 09 Oct 2018 13:25:09 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:51724) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g9vkq-00055B-1y; Tue, 09 Oct 2018 13:25:08 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.89) (envelope-from ) id 1g9vkp-00054R-5Z; Tue, 09 Oct 2018 18:25:07 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Tue, 9 Oct 2018 18:25:01 +0100 Message-Id: <20181009172501.17353-4-peter.maydell@linaro.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20181009172501.17353-1-peter.maydell@linaro.org> References: <20181009172501.17353-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH 3/3] block/qcow2-bitmap: Don't take address of fields in packed structs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" Taking the address of a field in a packed struct is a bad idea, because it might not be actually aligned enough for that pointer type (and thus cause a crash on dereference on some host architectures). Newer versions of clang warn about this. Avoid the bug by not using the "modify in place" byte swapping functions. There are a few places where the in-place swap function is used on something other than a packed struct field; we convert those anyway, for consistency. This patch was produced with the following spatch script: @@ expression E; @@ -be16_to_cpus(&E); +E =3D be16_to_cpu(E); @@ expression E; @@ -be32_to_cpus(&E); +E =3D be32_to_cpu(E); @@ expression E; @@ -be64_to_cpus(&E); +E =3D be64_to_cpu(E); @@ expression E; @@ -cpu_to_be16s(&E); +E =3D cpu_to_be16(E); @@ expression E; @@ -cpu_to_be32s(&E); +E =3D cpu_to_be32(E); @@ expression E; @@ -cpu_to_be64s(&E); +E =3D cpu_to_be64(E); Signed-off-by: Peter Maydell --- block/qcow2-bitmap.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index ba978ad2aac..74f7638e03c 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -118,7 +118,7 @@ static inline void bitmap_table_to_be(uint64_t *bitmap_= table, size_t size) size_t i; =20 for (i =3D 0; i < size; ++i) { - cpu_to_be64s(&bitmap_table[i]); + bitmap_table[i] =3D cpu_to_be64(bitmap_table[i]); } } =20 @@ -231,7 +231,7 @@ static int bitmap_table_load(BlockDriverState *bs, Qcow= 2BitmapTable *tb, } =20 for (i =3D 0; i < tb->size; ++i) { - be64_to_cpus(&table[i]); + table[i] =3D be64_to_cpu(table[i]); ret =3D check_table_entry(table[i], s->cluster_size); if (ret < 0) { goto fail; @@ -394,20 +394,20 @@ fail: =20 static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry) { - be64_to_cpus(&entry->bitmap_table_offset); - be32_to_cpus(&entry->bitmap_table_size); - be32_to_cpus(&entry->flags); - be16_to_cpus(&entry->name_size); - be32_to_cpus(&entry->extra_data_size); + entry->bitmap_table_offset =3D be64_to_cpu(entry->bitmap_table_offset); + entry->bitmap_table_size =3D be32_to_cpu(entry->bitmap_table_size); + entry->flags =3D be32_to_cpu(entry->flags); + entry->name_size =3D be16_to_cpu(entry->name_size); + entry->extra_data_size =3D be32_to_cpu(entry->extra_data_size); } =20 static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry) { - cpu_to_be64s(&entry->bitmap_table_offset); - cpu_to_be32s(&entry->bitmap_table_size); - cpu_to_be32s(&entry->flags); - cpu_to_be16s(&entry->name_size); - cpu_to_be32s(&entry->extra_data_size); + entry->bitmap_table_offset =3D cpu_to_be64(entry->bitmap_table_offset); + entry->bitmap_table_size =3D cpu_to_be32(entry->bitmap_table_size); + entry->flags =3D cpu_to_be32(entry->flags); + entry->name_size =3D cpu_to_be16(entry->name_size); + entry->extra_data_size =3D cpu_to_be32(entry->extra_data_size); } =20 static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_= size) --=20 2.19.0