From patchwork Wed Aug 29 09:23:27 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shivaprasad G Bhat X-Patchwork-Id: 963336 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 420gDc54w9z9ryt for ; Wed, 29 Aug 2018 19:24:16 +1000 (AEST) Received: from localhost ([::1]:41958 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fuwhy-00087e-5H for incoming@patchwork.ozlabs.org; Wed, 29 Aug 2018 05:24:14 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59191) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fuwhQ-00085i-7o for qemu-devel@nongnu.org; Wed, 29 Aug 2018 05:23:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fuwhL-0003A2-8T for qemu-devel@nongnu.org; Wed, 29 Aug 2018 05:23:39 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:33722 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fuwhK-00039H-Ro for qemu-devel@nongnu.org; Wed, 29 Aug 2018 05:23:35 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7T9JcnP063492 for ; Wed, 29 Aug 2018 05:23:34 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2m5n8rrh07-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 29 Aug 2018 05:23:33 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 29 Aug 2018 10:23:29 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7T9NTPq31391996 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 29 Aug 2018 09:23:29 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 651FF52050; Wed, 29 Aug 2018 12:23:25 +0100 (BST) Received: from lep8c.aus.stglabs.ibm.com (unknown [9.40.192.207]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id B8FC852057; Wed, 29 Aug 2018 12:23:24 +0100 (BST) From: Shivaprasad G Bhat To: riku.voipio@iki.fi, laurent@vivier.eu Date: Wed, 29 Aug 2018 04:23:27 -0500 User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 18082909-0028-0000-0000-000002F13FDC X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18082909-0029-0000-0000-000023AA9B19 Message-Id: <153553435604.51992.5640085189104207249.stgit@lep8c.aus.stglabs.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-08-29_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808290103 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCH v3] linux-user: elf: mmap all the target-pages of hostpage for data segment 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: qemu-ppc@nongnu.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" If the hostpage size is greater than the TARGET_PAGESIZE, the target-pages of size TARGET_PAGESIZE are marked valid only till the length requested during the elfload. The glibc attempts to consume unused space in the last page of data segment(__libc_memalign() in elf/dl-minimal.c). If PT_LOAD p_align is greater than or equal to hostpage size, the GLRO(dl_pagesize) is actually the host pagesize as set in the auxillary vectors. So, there is no explicit mmap request for the remaining target-pages on the last hostpage. The glibc assumes that particular space as available and subsequent attempts to use those addresses lead to crash as the target_mmap has not marked them valid for those target-pages. The issue is seen when trying to chroot to 16.04-x86_64 ubuntu on a PPC64 host where the fork fails to access the thread_id as it is allocated on a page not marked valid. The recent glibc doesn't have checks for thread-id in fork, but the issue can manifest somewhere else, none the less. The fix here is to map all the target-pages of the hostpage during the elfload if the p_align is greater than or equal to hostpage size, for data segment to allow the glibc for proper consumption. Signed-off-by: Shivaprasad G Bhat Reviewed-by: Laurent Vivier --- v2: https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg05943.html Changes from v2: - Simplified the macro as suggested. - Fixed some grammatical error in commit message. v1: https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg05730.html Changes from v1: - Made the conditionals consistent with the commit "33143c446e" and changed the commit message accordingly. linux-user/elfload.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 8638612aec..6ead0d11c6 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1437,7 +1437,10 @@ struct exec #define QMAGIC 0314 /* Necessary parameters */ -#define TARGET_ELF_EXEC_PAGESIZE TARGET_PAGE_SIZE +#define TARGET_ELF_EXEC_PAGESIZE \ + (((eppnt->p_align & ~qemu_host_page_mask) != 0) ? \ + TARGET_PAGE_SIZE : MAX(qemu_host_page_size, TARGET_PAGE_SIZE)) +#define TARGET_ELF_PAGELENGTH(_v) ROUND_UP((_v), TARGET_ELF_EXEC_PAGESIZE) #define TARGET_ELF_PAGESTART(_v) ((_v) & \ ~(abi_ulong)(TARGET_ELF_EXEC_PAGESIZE-1)) #define TARGET_ELF_PAGEOFFSET(_v) ((_v) & (TARGET_ELF_EXEC_PAGESIZE-1)) @@ -2279,7 +2282,7 @@ static void load_elf_image(const char *image_name, int image_fd, for (i = 0; i < ehdr->e_phnum; i++) { struct elf_phdr *eppnt = phdr + i; if (eppnt->p_type == PT_LOAD) { - abi_ulong vaddr, vaddr_po, vaddr_ps, vaddr_ef, vaddr_em; + abi_ulong vaddr, vaddr_po, vaddr_ps, vaddr_ef, vaddr_em, vaddr_len; int elf_prot = 0; if (eppnt->p_flags & PF_R) elf_prot = PROT_READ; @@ -2289,8 +2292,9 @@ static void load_elf_image(const char *image_name, int image_fd, vaddr = load_bias + eppnt->p_vaddr; vaddr_po = TARGET_ELF_PAGEOFFSET(vaddr); vaddr_ps = TARGET_ELF_PAGESTART(vaddr); + vaddr_len = TARGET_ELF_PAGELENGTH(eppnt->p_filesz + vaddr_po); - error = target_mmap(vaddr_ps, eppnt->p_filesz + vaddr_po, + error = target_mmap(vaddr_ps, vaddr_len, elf_prot, MAP_PRIVATE | MAP_FIXED, image_fd, eppnt->p_offset - vaddr_po); if (error == -1) {