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Thu, 11 Feb 2021 08:30:09 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-452-16IVXu6iNoaXyH3pF0IcoQ-1; Thu, 11 Feb 2021 08:30:04 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5AA3580404F; Thu, 11 Feb 2021 13:30:03 +0000 (UTC) Received: from thuth.com (ovpn-112-46.ams2.redhat.com [10.36.112.46]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4E80E2BFE7; Thu, 11 Feb 2021 13:30:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613050207; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=ZLSxsDaC68a8VLJ5/p55dCqnJ+rUSp0X3QepOh4w9+w=; b=YiKiEQQy1Mr35ZRCEg+CfK1bEvyJWfvVDDC4gmyke0c7ccmd/21nc2ycqaxnn3aXtm+SYY mnFuQtWL8WhinM3hywefCrSMpmFrVhuSd8wTZMrFfdPKVwhr2OCQXZ225B9CvAfd7hzfFM qGQTVd6zwd/9ymJW3AE5LRN+cw2Lx4k= X-MC-Unique: 16IVXu6iNoaXyH3pF0IcoQ-1 From: Thomas Huth To: Laurent Vivier , qemu-devel@nongnu.org Subject: [PATCH] linux-user/syscall: Silence warning from the undefined behavior sanitizer Date: Thu, 11 Feb 2021 14:29:59 +0100 Message-Id: <20210211132959.574168-1-thuth@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.569, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" When compiling QEMU with -fsanitize=3Dundefined, there is a warning when running "make check-tcg": TEST linux-test on m68k ../linux-user/syscall.c:10499:34: runtime error: member access within misaligned address 0x00008006df3c for type 'struct linux_dirent64', which requires 8 byte alignment 0x00008006df3c: note: pointer points here 00 00 00 00 68 03 28 00 00 00 00 00 5b 96 3e e4 61 4b 05 26 18 00 04 2e= 00 00 00 00 da 3f 18 00 ^ It's likely not an issue in reality, since I assume that on hosts where the alignment really matters (like sparc64), the Linux kernel likely adds the right padding. Anyway, let's use the stw_p() / stq_p() accessor helpers here to silence the warning and thus to allow to compile the code with -fsanitize=3Dundefined, too. Signed-off-by: Thomas Huth --- linux-user/syscall.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 34760779c8..50de535ade 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -10491,20 +10491,22 @@ static abi_long do_syscall1(void *cpu_env, int nu= m, abi_long arg1, return -TARGET_EFAULT; ret =3D get_errno(sys_getdents64(arg1, dirp, count)); if (!is_error(ret)) { - struct linux_dirent64 *de; + char *de; int len =3D ret; int reclen; - de =3D dirp; + de =3D (char *)dirp; + #define de64(x) offsetof(struct linux_dirent64, x) while (len > 0) { - reclen =3D de->d_reclen; + reclen =3D lduw_he_p(de + de64(d_reclen)); if (reclen > len) break; - de->d_reclen =3D tswap16(reclen); - tswap64s((uint64_t *)&de->d_ino); - tswap64s((uint64_t *)&de->d_off); - de =3D (struct linux_dirent64 *)((char *)de + reclen); + stw_p(de + de64(d_reclen), reclen); + stq_p(de + de64(d_ino), ldq_he_p(de + de64(d_ino))); + stq_p(de + de64(d_off), ldq_he_p(de + de64(d_off))); + de +=3D reclen; len -=3D reclen; } + #undef de64 } unlock_user(dirp, arg2, ret); } --=20 2.27.0