From patchwork Thu Aug 3 01:53:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 709581 Delivered-To: patch@linaro.org Received: by 2002:ab3:5b92:0:b0:238:c968:2573 with SMTP id j18csp1354126ltf; Wed, 2 Aug 2023 18:54:29 -0700 (PDT) X-Google-Smtp-Source: APBJJlFnkap3CYC86EawD4Y1f+O6JFvwRyY8jYGXIF15WwG+Zu1GQ3EmUvwIKC9/XHubEZ32x/Xy X-Received: by 2002:a05:620a:44cc:b0:767:f116:1b92 with SMTP id y12-20020a05620a44cc00b00767f1161b92mr22162511qkp.38.1691027669377; Wed, 02 Aug 2023 18:54:29 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1691027669; cv=none; d=google.com; s=arc-20160816; b=ZdbtbyM6f9wb9MNyBLjIbtxXZpcLjmIeFfn38cVIUikkFe1KpxCwEpTNsnD+hgxjb8 I1H/FcBP+ybEegj9bm39xOKVPOjU+wo8Q8G4qFfTZpv+WQeFwUA/kbD9uLwGhlthTJzV fNItsNMgOe9za12fdy/V8Mn1rzXvn00H1TGfkEXZpmNKoFt48C7yeFbAMlUVNhgfuyhT frjywlSEY1ycWIBWGXY27PKtA3R3sSLJ/vMEuyJxMU5n9rUdp+YqMmj4xOFaLsjLpAD6 k54HiB9nGcnPOU7aC1QHeB8uMQX2hbMeMJPFXWZqiZ3N6FJIOUGFLZYL9D/qtrIbqGQY Nbuw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:content-transfer-encoding :mime-version:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=iTYiVzZgwnSBm2cJQnzOd6IorKWpOrXyW6rl98Yh7OU=; fh=fmVFRXV+XPDbp8+eafcQB359/x6dDRQDsVzPMZJ0Hao=; b=hQenISEfMwRPtKTx/tTyp+AL9u0oJGyx3Wh19BfSMGDrc6CrF5ZnuKJDfeKY5r/y8a TREHlPlqSQJI9YVrFp8wcYsI+eOe2fmGWzUAX6Mh0TeSM6y37jD3qm/GNw65HwejvXPY u5BFyQHCpVp6mqkg8SACImZURR9v1bk1Jm8aV6fsINxPKdWW7jwWwqgFTNIuN1XOmEDe RWUlCCv97eKg0vcySD/NoWsqP5Y+IdUv6PrE8I2khN+FFNJ6urmFJv6RI0X86Jjyg+g9 OiukkU8ITeRrGimD2Nmrh9kXGjuos6cskc/wUMj5dUw3vQzRl+4UztANt0Go9aaJF2Hm CcmQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b="pt7YBuQ/"; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org. [209.51.188.17]) by mx.google.com with ESMTPS id q28-20020a05620a025c00b00767356571a6si7872768qkn.785.2023.08.02.18.54.29 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Wed, 02 Aug 2023 18:54:29 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b="pt7YBuQ/"; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qRNWl-0000jR-1Y; Wed, 02 Aug 2023 21:53:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qRNWg-0000iA-DQ for qemu-devel@nongnu.org; Wed, 02 Aug 2023 21:53:18 -0400 Received: from mail-pg1-x533.google.com ([2607:f8b0:4864:20::533]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qRNWe-0000oh-Hh for qemu-devel@nongnu.org; Wed, 02 Aug 2023 21:53:18 -0400 Received: by mail-pg1-x533.google.com with SMTP id 41be03b00d2f7-55b22f82ac8so1092514a12.1 for ; Wed, 02 Aug 2023 18:53:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1691027595; x=1691632395; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=iTYiVzZgwnSBm2cJQnzOd6IorKWpOrXyW6rl98Yh7OU=; b=pt7YBuQ/7O08Bl4RKc8BNEVYPl6kjlWa6Gr+dxCwfHDUeshjfsf25iSbs/Cbl6P8la YR3X6hChjLzDwy0IHgVWwD1p5pRPvTCNniwZHbNXwqfw3hbpTEIrlyJ7lPI5AVkb0fej yybHH/e5zzECrWNkbNDAubA01lYS6zkLxqS8DPGRfuYA026Px6kFHeVKmuytoFowTZTE TxxV0PWQHu16jacNWCUIk3N6qUSbrEoFF48HpP0ePiuEWbew4MFZ4Qolk7VfAJZeAVsK /GICeDKRo3cKMP9VI2K+ROoqB7nGR2t5cfiQjU98AsY15cnGxObOskYitLsp3Rd9yA7A J23g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691027595; x=1691632395; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=iTYiVzZgwnSBm2cJQnzOd6IorKWpOrXyW6rl98Yh7OU=; b=OwF4sxLnmblsQm7yMa71M5VaxUe3qtbzylEEMrcYjdHprDqlSKidKoqxEfJvk5iV7v qhm+OxJi6hwFVShYcuvd7yBaPc59yFfAkNuh3yJzZFc+c12z08tB/5M7Spp/+Q+o9uDZ hGG/IitfG3aCXhR85602Wv4Z4mS9B56Mp4qlRufJesF25VdKXChAZv5P+3ebvH39TlCO LT7KrMiL4/tnDPYz51o4YtL48oZnF4FU+SoJ94Hkykksv53lwTEwTKCaiwoMkfWKAVlC ML440sgPXm0o0nxtknGYxy0QYfA4wZeRZJau4PHPJM3yfuJwQ2/Z2zVCIzIAr3Ubfx3B APsA== X-Gm-Message-State: ABy/qLaG70VMVVFZw4FJv4MpB7C51z4RgGSzxCShHiP/pXHt1f7rWbZa WgZPGG5t+6TszSoxoy+J45An0hCEZWBewN0fyVY= X-Received: by 2002:a17:90b:1bc6:b0:268:5aaf:fbe with SMTP id oa6-20020a17090b1bc600b002685aaf0fbemr22748015pjb.10.1691027594941; Wed, 02 Aug 2023 18:53:14 -0700 (PDT) Received: from stoup.. ([2602:47:d490:6901:b659:bbad:1a22:7ef9]) by smtp.gmail.com with ESMTPSA id s25-20020a63a319000000b005649cee408fsm157123pge.0.2023.08.02.18.53.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Aug 2023 18:53:14 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: deller@gmx.de, laurent@vivier.eu, akihiko.odaki@daynix.com, joel@jms.id.au Subject: [PATCH v7 13/14] linux-user: Adjust initial brk when interpreter is close to executable Date: Wed, 2 Aug 2023 18:53:01 -0700 Message-Id: <20230803015302.407219-14-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230803015302.407219-1-richard.henderson@linaro.org> References: <20230803015302.407219-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::533; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x533.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org From: Helge Deller While we attempt to load a ET_DYN executable far away from TASK_UNMAPPED_BASE, we are not completely in control of the address space layout. If the interpreter lands close to the executable, leaving insufficient heap space, move brk. Signed-off-by: Helge Deller [rth: Re-order after ELF_ET_DYN_BASE patch so that we do not "temporarily break" tsan, and also to minimize the changes required. Remove image_info.reserve_brk as unused.] Signed-off-by: Richard Henderson --- linux-user/qemu.h | 1 - linux-user/elfload.c | 51 +++++++++++++------------------------------- 2 files changed, 15 insertions(+), 37 deletions(-) diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 802794db63..4b0c9da0dc 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -31,7 +31,6 @@ struct image_info { abi_ulong end_data; abi_ulong start_brk; abi_ulong brk; - abi_ulong reserve_brk; abi_ulong start_mmap; abi_ulong start_stack; abi_ulong stack_limit; diff --git a/linux-user/elfload.c b/linux-user/elfload.c index fef9a0bc8f..bf747a15b5 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -3120,27 +3120,6 @@ static void load_elf_image(const char *image_name, int image_fd, load_map_flags = 0; } if (pinterp_name != NULL) { - /* - * This is the main executable. - * - * Reserve extra space for brk. - * We hold on to this space while placing the interpreter - * and the stack, lest they be placed immediately after - * the data segment and block allocation from the brk. - * - * 16MB is chosen as "large enough" without being so large as - * to allow the result to not fit with a 32-bit guest on a - * 32-bit host. However some 64 bit guests (e.g. s390x) - * attempt to place their heap further ahead and currently - * nothing stops them smashing into QEMUs address space. - */ -#if TARGET_LONG_BITS == 64 - info->reserve_brk = 32 * MiB; -#else - info->reserve_brk = 16 * MiB; -#endif - hiaddr += info->reserve_brk; - if (ehdr->e_type == ET_EXEC) { /* * Make sure that the low address does not conflict with @@ -3229,7 +3208,8 @@ static void load_elf_image(const char *image_name, int image_fd, info->end_code = 0; info->start_data = -1; info->end_data = 0; - info->brk = 0; + /* Usual start for brk is after all sections of the main executable. */ + info->brk = TARGET_PAGE_ALIGN(hiaddr); info->elf_flags = ehdr->e_flags; prot_exec = PROT_EXEC; @@ -3323,9 +3303,6 @@ static void load_elf_image(const char *image_name, int image_fd, info->end_data = vaddr_ef; } } - if (vaddr_em > info->brk) { - info->brk = vaddr_em; - } #ifdef TARGET_MIPS } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) { Mips_elf_abiflags_v0 abiflags; @@ -3654,6 +3631,19 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) if (elf_interpreter) { load_elf_interp(elf_interpreter, &interp_info, bprm->buf); + /* + * While unusual because of ELF_ET_DYN_BASE, if we are unlucky + * with the mappings the interpreter can be loaded above but + * near the main executable, which can leave very little room + * for the heap. + * If the current brk has less than 16MB, use the end of the + * interpreter. + */ + if (interp_info.brk > info->brk && + interp_info.load_bias - info->brk < 16 * MiB) { + info->brk = interp_info.brk; + } + /* If the program interpreter is one of these two, then assume an iBCS2 image. Otherwise assume a native linux image. */ @@ -3707,17 +3697,6 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) bprm->core_dump = &elf_core_dump; #endif - /* - * If we reserved extra space for brk, release it now. - * The implementation of do_brk in syscalls.c expects to be able - * to mmap pages in this space. - */ - if (info->reserve_brk) { - abi_ulong start_brk = TARGET_PAGE_ALIGN(info->brk); - abi_ulong end_brk = TARGET_PAGE_ALIGN(info->brk + info->reserve_brk); - target_munmap(start_brk, end_brk - start_brk); - } - return 0; }