From patchwork Tue Sep 25 08:54:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Vivier X-Patchwork-Id: 974305 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=vivier.eu Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 42KFKb6lplz9sBW for ; Tue, 25 Sep 2018 18:56:03 +1000 (AEST) Received: from localhost ([::1]:51703 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g4j8T-0003O2-37 for incoming@patchwork.ozlabs.org; Tue, 25 Sep 2018 04:56:01 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47391) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g4j7p-0003Jv-MS for qemu-devel@nongnu.org; Tue, 25 Sep 2018 04:55:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g4j7m-0000CD-7O for qemu-devel@nongnu.org; Tue, 25 Sep 2018 04:55:21 -0400 Received: from mout.kundenserver.de ([212.227.126.187]:41231) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1g4j7l-0000Bg-TK for qemu-devel@nongnu.org; Tue, 25 Sep 2018 04:55:18 -0400 Received: from localhost.localdomain ([78.238.229.36]) by mrelayeu.kundenserver.de (mreue011 [212.227.15.167]) with ESMTPSA (Nemesis) id 1N6bTa-1fhvCm2yo2-018744; Tue, 25 Sep 2018 10:55:06 +0200 From: Laurent Vivier To: qemu-devel@nongnu.org Date: Tue, 25 Sep 2018 10:54:30 +0200 Message-Id: <20180925085432.3791-4-laurent@vivier.eu> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180925085432.3791-1-laurent@vivier.eu> References: <20180925085432.3791-1-laurent@vivier.eu> X-Provags-ID: V03:K1:eBxRn6kvGqX22mPCh8g/0EUkmpS8p+LDLkKOSNxuAokPWCPY+UM n4uIs8asX+99pjgAfSvq/GRHsQeudUXAyDWjZV++ND17MTz8kmipq2edoqGwMiBsy3HSkYI mznXZK5qmFWw4ZQZcNl8+TrDevSMTsOBeb2ZQo30fzO74msr//inQWVaoM8nJlv5yin6xeU SWcT/Ju1UEowpyh7Egx1g== X-UI-Out-Filterresults: notjunk:1; V01:K0:v9KiQ/bhLr4=:D9Jpe3IWpu5c+KqJgGrPoL VKOoTr92j9Ktf0Ps2/zPB7ePKxOqrhp5v/qZxufWXQ+a84I/Ci+XS+4C1UAwunesCGOawQqcg DpWt2ZK655/Nu+9ZRueSNR7p745jRcLMPPxFWNw1kIsL1A+bMDVOJRSHpwABgbmGzw4aJgJ0+ rE7zMgWlyMZORu0s6x+vI02udrhZ0igY1ahTInCvlY6HlwCFE9vaYhYeNT30b2AsaZxB5Qtq4 wZWJPPWL2Zf63eg5p2JAY1Zqqo+8RlPkwRlasi+cgwp9N+aUwwE5yA7CwK+gh79y+9DajFwES yUSBYsJ4Y47ctC/QStftLnOZ9in89U21iurm5SB0kRDAPcOCLfmIgMvZcp+soQljyPCq7r1BY L3QL2SakJTDuPBBJ8mKQ9f1f02isaAf+4cwi09zbN4XVCZjeBNYgKKH/TAt9ktrA4yh1nWGQE 998hPdWuDGNX0ivrPr3V/MDn1pSaApn1TRPwRFNfTQdtJzevjGFYOfZey88WbTOm8neXsmovC j7U+rg23/2R3rnpPbB81JtN0CvN5FBuUsR71OoX6B4I+j4xRNFgMFxj1hvQ8fa1AMyZDcHuIw g3MjxiCf6nesuFipLt56GU6fFx3kbWJTMAqOp41oVtNVFK9bdaP3PjND6Wvs/+/rtPDKEAcM+ ZzUmBs4lXy7hgP8C8P8x0jiKhrggt4wVLx1jeJwhNDnEhEySBKlu8oMh2YTrn1Sl79qM= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 212.227.126.187 Subject: [Qemu-devel] [PULL 3/5] 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: Riku Voipio , Shivaprasad G Bhat , Laurent Vivier Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Shivaprasad G Bhat 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 Message-Id: <153553435604.51992.5640085189104207249.stgit@lep8c.aus.stglabs.ibm.com> Signed-off-by: Laurent Vivier --- 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) {