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 E9E76C27C7B for ; Wed, 12 Jun 2024 16:41:45 +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=mVdDozQhgLCHWTGkIS279cpqPxFfjKVFZDQpKU4sKrQ=; b=srJ/bKJQC5SGThIM48xj6z1jLl OkrEnGgso5XJ2KOopTrxitxXHVY1y0bEUyy9NJV5mFUgIpkMj1sFWX0xt8hoBZEL+OEmwo833z0lg oUdsAEA9zuTvdeMT/htdsq4iKJZjGrTsVSoqcn5xSohyXzmN3Nny8fz+YEUZoTu0UXQIfY3E+wHtm BQyHIZcSFues131pUBKqU0mnlZTIIBWShss5h/i5RfN2NU2zIENsWJQabN6nLI1CZhL957j1nXUJP zzIXJhdhs0oDWKLj4aGeLUlLLaclDjAwif8GAFZCAgx1aT81JW/3rgTc2a8CGIq1B3GvBwlQCUct2 zwVLBXwQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sHR2f-0000000DPvX-2S8t; Wed, 12 Jun 2024 16:41:45 +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 1sHR2a-0000000DPsW-0FfE for linux-um@lists.infradead.org; Wed, 12 Jun 2024 16:41:44 +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=mVdDozQhgLCHWTGkIS279cpqPxFfjKVFZDQpKU4sKrQ=; t=1718210499; x=1719420099; b=x4OhydiYL+JCFZTUOxM5XgoyqHeB5PZ9dPMQ/3TTARtJw+J vfOn9Qc9XCi6g8FbYlVfIXE0HCQbEfocgeksvqBcswoW1Zjz+RZam+t6Mi9fFLwHUJ3A+9HGzXeBL mlPO3bQpyaZz+rTx0HjM3I/h+sPHAIMj3SnjibWFqrovaIdGPvZ4cpw8DVYoM/sM6X9oyvZ2l++LX 15Qpnl8ZdvmOTyypyNeQpjJa41X/VROdjWBZoowJB3mRDiNnaJzpe1DeLiR7xEpeKyEw6EB/x01pw 9/bUpskkn1azZTEqLcM9cpmomDJ7J0sw0mFrv7A/yXMtT58k478cyTGyD1G4rSTg==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1sHR2X-0000000AUQy-2brp; Wed, 12 Jun 2024 18:41:38 +0200 From: benjamin@sipsolutions.net To: linux-um@lists.infradead.org Cc: Benjamin Berg Subject: [PATCH v4 2/5] um: Limit TASK_SIZE to the addressable range Date: Wed, 12 Jun 2024 18:41:05 +0200 Message-ID: <20240612164108.1742106-3-benjamin@sipsolutions.net> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240612164108.1742106-1-benjamin@sipsolutions.net> References: <20240612164108.1742106-1-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-20240612_094140_144075_16390F45 X-CRM114-Status: GOOD ( 10.06 ) 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 --- 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 0d8b1a73cd5b..5ab1a92b6bf7 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -337,11 +337,16 @@ 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 > 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(); -- 2.45.1