From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48017C433E3 for ; Mon, 27 Jul 2020 12:28:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 115FB2074F for ; Mon, 27 Jul 2020 12:28:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="pJ5LGBBm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 115FB2074F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58146 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k02FB-0005r9-Bb for qemu-devel@archiver.kernel.org; Mon, 27 Jul 2020 08:28:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37008) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k02At-00075N-D4 for qemu-devel@nongnu.org; Mon, 27 Jul 2020 08:24:11 -0400 Received: from mail-wr1-x441.google.com ([2a00:1450:4864:20::441]:38731) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1k02Ar-0006Qx-IW for qemu-devel@nongnu.org; Mon, 27 Jul 2020 08:24:11 -0400 Received: by mail-wr1-x441.google.com with SMTP id a14so14694294wra.5 for ; Mon, 27 Jul 2020 05:24:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=376gksLE0t2X1o47gQBQYWuWEK67vP0MVufWmCqpGJE=; b=pJ5LGBBmooA25MiX7uQOM2uAseNIGPbCjcRpIe3XrAAc8OQgw/6Kvh31AlzcMpUotr qTcnjS3UZUmfNdcwj1ZLhxfIqUiBKQTXjrEKbbIBllz3qFxIvjDQ5GTKVwfgFq9Ej3lF ckVj4JDbA3xhHZospNZFTGa2m4N9Icx54mSxVdjLICdHkxf7OJuFtc+1HIWcLkoEpanc EBg2Bfz4cZiT8mszclI6Se6qAenSkeznH5R7qI/8CfIu2ygbHsHg4hSWaSCpAA/vQOnR b8tsH5NrresCklGtwBt2Y14Yb1f4TTKE2SPxyjd6Bbmp+oTeSZdEYiJDtcxgor+YhuIF NW5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=376gksLE0t2X1o47gQBQYWuWEK67vP0MVufWmCqpGJE=; b=oZ98ORQsZcCJ6+KSE0D1HddVWY48bQJnCjeACdW2ZbtywVpDIzZpqGuBY1BzVMJHo0 LOV6hYNqmXGB2kB3MlH1US5T+xLdaCY+hQkAJEbmqTlWsEczNng7KkRZL8t/GnkfIXMD 3xPQEBtuUKqZQFcAh6cK+vniA3vqKKjykGD2+t0rp+gN8mXSI3UMyE8N2QWUIYr5XILP 1Xby/6Gh/88y0rwm9GQsDetMDfidMLLQo8ue3zOWVmjmMwRQ+PYXZ2QqBeSBjwZqPsFc 40qlxTI2jDVBu007BZ/xZ7L7hBT+uXrmt2PfZuMy478ruQskMoBJBT94TraBNz/IBc6G p2rQ== X-Gm-Message-State: AOAM530rdxqC7XSvH6xYf8nPPjdr9DjJtZWsKrNO2f3dDYehnNux51uL w5mqJyDOrH7KBnOfSbx+5erI2A== X-Google-Smtp-Source: ABdhPJzVvYsbG26G9MtzkryvkyqBz6s8Mst+OApfrb98hxmyWXHTtu9hcOAA5uDH/wDPgyJDVi8WEA== X-Received: by 2002:a5d:5710:: with SMTP id a16mr12623788wrv.217.1595852648232; Mon, 27 Jul 2020 05:24:08 -0700 (PDT) Received: from zen.linaroharston ([51.148.130.216]) by smtp.gmail.com with ESMTPSA id x204sm22274048wmg.2.2020.07.27.05.24.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Jul 2020 05:24:03 -0700 (PDT) Received: from zen.lan (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 2735F1FF96; Mon, 27 Jul 2020 13:23:58 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: peter.maydell@linaro.org Subject: [PULL 08/16] linux-user: don't use MAP_FIXED in pgd_find_hole_fallback Date: Mon, 27 Jul 2020 13:23:49 +0100 Message-Id: <20200727122357.31263-9-alex.bennee@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200727122357.31263-1-alex.bennee@linaro.org> References: <20200727122357.31263-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::441; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x441.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. 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 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: , Cc: Richard Henderson , =?UTF-8?q?Alex=20Benn=C3=A9e?= , qemu-devel@nongnu.org, Laurent Vivier Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Plain MAP_FIXED has the undesirable behaviour of splatting exiting maps so we don't actually achieve what we want when looking for gaps. We should be using MAP_FIXED_NOREPLACE. As this isn't always available we need to potentially check the returned address to see if the kernel gave us what we asked for. Fixes: ad592e37dfc ("linux-user: provide fallback pgd_find_hole for bare chroots") Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson Message-Id: <20200724064509.331-9-alex.bennee@linaro.org> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 0b1298b3c91..20872e793e4 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -173,6 +173,9 @@ extern int daemon(int, int); #ifndef MAP_ANONYMOUS #define MAP_ANONYMOUS MAP_ANON #endif +#ifndef MAP_FIXED_NOREPLACE +#define MAP_FIXED_NOREPLACE 0 +#endif #ifndef ENOMEDIUM #define ENOMEDIUM ENODEV #endif diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 7e7f642332d..fe9dfe795dd 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2134,12 +2134,15 @@ static uintptr_t pgd_find_hole_fallback(uintptr_t guest_size, uintptr_t brk, /* we have run out of space */ return -1; } else { - int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE | MAP_FIXED; + int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE | + MAP_FIXED_NOREPLACE; void * mmap_start = mmap((void *) align_start, guest_size, PROT_NONE, flags, -1, 0); if (mmap_start != MAP_FAILED) { munmap((void *) align_start, guest_size); - return (uintptr_t) mmap_start + offset; + if (MAP_FIXED_NOREPLACE || mmap_start == (void *) align_start) { + return (uintptr_t) mmap_start + offset; + } } base += qemu_host_page_size; } @@ -2307,9 +2310,8 @@ static void pgb_reserved_va(const char *image_name, abi_ulong guest_loaddr, /* Widen the "image" to the entire reserved address space. */ pgb_static(image_name, 0, reserved_va, align); -#ifdef MAP_FIXED_NOREPLACE + /* osdep.h defines this as 0 if it's missing */ flags |= MAP_FIXED_NOREPLACE; -#endif /* Reserve the memory on the host. */ assert(guest_base != 0); -- 2.20.1