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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 911EDC30653 for ; Thu, 4 Jul 2024 16:27:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NYxm6HJmMWAKJ6fAshLmO7RJHKejdCZeUmDhjTK4Zwg=; b=CoxdXdFkWEJFR4Y9l1IrTA650K LRSQojvbNYOQWD1WjFgygOhMDHxFbS/4PkXgwR3CxqhOrYCsCpkMaTOBn7pn/6RT3fpOz3oS/bm/N pqiQqrVOgO3PzVVlYgctS5bglHwpnlDRZ4wUkX9+2nOZ+EKZtKDcyiocfq+O1gcEVJDZHBOB/GkWg P2qjp8IaiiQteT92/tS8sS2M0g5k9oXDNzATx7kqqEDqzObKA0x2XYy+eJWOEPtlJUjgNlx1XLqY5 eV6LsMsDfKgckU9q1IecoLUtm/KhxR6uaEv1q06LgC6u/04+0R07jd2KE2qvWrG7e3qaY/diprv7H D095iC3g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sPPJL-0000000DqIe-0jOe; Thu, 04 Jul 2024 16:27:55 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:242:246e::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sPPJI-0000000DqH2-2y4g for linux-um@lists.infradead.org; Thu, 04 Jul 2024 16:27:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Content-Type:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=NYxm6HJmMWAKJ6fAshLmO7RJHKejdCZeUmDhjTK4Zwg=; t=1720110472; x=1721320072; b=c4W8+QZmTdLUaAnH87fmLOkVMM6G4yZTg8aoMljzp8+a+Ja I9qqZiCzYz1Hl9/GU9eZCBn5T9uc1gooraX5Ymur1ZPfJmiaxAsYZzEN7eebNAN93Z2XrTbeUvyx9 nmhY9AQsqv9jKJSbzEBWTCeYRAnFFfUsiD1XUZDnF95Iv/lWH1evWex2151KF6B/WS0+9cMCL8eZC Jmua5b2tKwfkC6P8FMSaIA2B4FgTcjvVsOorNRWmRDb+egmBzFjulVsl9ar7UILkK3KX2sCXADhd4 faB0cx1uVDxXOAVta7Sd+uXX+jSV57xu0La/XxrImYcCY1cdjNUJzrgbE7mf7pKQ==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1sPPJE-0000000DOu8-2Yfu; Thu, 04 Jul 2024 18:27:49 +0200 From: Benjamin Berg To: linux-um@lists.infradead.org Cc: Benjamin Berg Subject: [PATCH v7 4/7] um: Limit TASK_SIZE to the addressable range Date: Thu, 4 Jul 2024 18:27:14 +0200 Message-ID: <20240704162717.1417338-5-benjamin@sipsolutions.net> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240704162717.1417338-1-benjamin@sipsolutions.net> References: <20240704162717.1417338-1-benjamin@sipsolutions.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240704_092752_771170_C93FD218 X-CRM114-Status: GOOD ( 10.09 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org From: Benjamin Berg We may have a TASK_SIZE from the host that is bigger than UML is able to address with a three-level pagetable. Guard against that by clipping the maximum TASK_SIZE to the maximum addressable area. Signed-off-by: Benjamin Berg --- v7: Fix integer overflow on 32 bit with 3-level page tables --- arch/um/kernel/um_arch.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 25cd2c6d7e95..f82dd4e854f3 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -334,11 +334,16 @@ int __init linux_main(int argc, char **argv) stub_start -= PAGE_SIZE; host_task_size = stub_start; + /* Limit TASK_SIZE to what is addressable by the page table */ + task_size = host_task_size; + if (task_size > (unsigned long long) PTRS_PER_PGD * PGDIR_SIZE) + task_size = PTRS_PER_PGD * PGDIR_SIZE; + /* * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps * out */ - task_size = host_task_size & PGDIR_MASK; + task_size = task_size & PGDIR_MASK; /* OS sanity checks that need to happen before the kernel runs */ os_early_checks(); -- 2.45.2