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 CF6F8CDD552 for ; Thu, 19 Sep 2024 12:45:50 +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=e8scBRWWo9W08vUFhaDXyigBOzLsHUQdgMahMtblGa8=; b=LG1+ZJnM6BWo7/EHTN1VWFqa1i d+R2BokwxXskU1gxbl1EQ1qAcY6CEOcE4TaYBcdf/w7C0YvHONe1HjTl7sDo4JguBgpQNnUBMq72W Z3i2oTVQ5bA+o2q4B+x2S6nkjgjMJ3JOYbM45UtQFLGL55hEdmwDb0kFoWUfM2aau32/Vb1ckHOqy gBq+3kc1fugWj/U7kp/7+2EjFRpjV1uRnI3O6CPko90WGjX2G4udobsgxEQoC12qj0xLRmYUJjZlf 4Ud1KZYJQuvXTHr19z+AFNS3gHxg9uPAkgHx6leSTXGc+G2ymFhlMVxQyWk62kgylHocF4kENY7bQ 5YYKVHrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1srGXe-0000000AGtw-1srP; Thu, 19 Sep 2024 12:45:50 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:242:246e::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1srGXb-0000000AGrf-20la for linux-um@lists.infradead.org; Thu, 19 Sep 2024 12:45:48 +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=e8scBRWWo9W08vUFhaDXyigBOzLsHUQdgMahMtblGa8=; t=1726749947; x=1727959547; b=AzfyrYd3GrBYL+fdMQdTxYTDN0XBvnSF80efF2bAsNrXDrH OxMt8hlwviEGcDP7/HngUALDhs418P70pfvKbia2QA+Btl7rh7v070QW2iGRN7pF+VkY15CJYc5vf NQTAD7vV8QyhGJY4xngVSTEnaMvE84CN4uk2xVvtI564hfZI800oOqu6s5JlMOlLzvavY7fkK4GAK EfzHU+6mJ25gLakWv/eEtRixodWV2W1FLJbLNTn9CgAfg++c9TpdXhZkj6TmpjFnR0BgBsdkbZRkK C4zypnqRHHDBWYmXcRjURsLqAijrMY4eHfw0C3yOkrrQoHQ6hatz2EbtsdgFztxQ==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1srGXZ-000000047AZ-0mvO; Thu, 19 Sep 2024 14:45:45 +0200 From: Benjamin Berg To: linux-um@lists.infradead.org Cc: Benjamin Berg Subject: [PATCH v9 07/10] um: Limit TASK_SIZE to the addressable range Date: Thu, 19 Sep 2024 14:45:08 +0200 Message-ID: <20240919124511.282088-8-benjamin@sipsolutions.net> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240919124511.282088-1-benjamin@sipsolutions.net> References: <20240919124511.282088-1-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-20240919_054547_622020_A93E03DD X-CRM114-Status: GOOD ( 11.11 ) 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 on 64-bit. Guard against that by clipping the maximum TASK_SIZE to the maximum addressable area. Signed-off-by: Benjamin Berg --- v9: This patch is technically not needed anymore, but does not hurt v7: Fix integer overflow on 32 bit with 3-level page tables 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 44589cbd4174..6f0bedbf048a 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -331,11 +331,16 @@ 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(); -- 2.46.0