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=-5.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 C74D5C04AAD for ; Mon, 6 May 2019 14:43:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9862121479 for ; Mon, 6 May 2019 14:43:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557153810; bh=9gbumceD6ikjDbZK1PP/dlsoDdVo2qH76kCkoJBKes8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=onfcM5YhJpedlR+3yOW2OVmMPh2Tnx5QC6YobwQNqeOhk6Y/S75s8v2iSB3Cq8J8n WPey21TPTHpJH3YN2vz4g1rojmrRLHkXx8ir/Cy6Or8laknXp/3NzQxkMorWMzpG4M HbN5BFaieLs6HyHMDYfB551B936Rkoy+0tadmcM0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728652AbfEFOn3 (ORCPT ); Mon, 6 May 2019 10:43:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:39052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727945AbfEFOn2 (ORCPT ); Mon, 6 May 2019 10:43:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 940802087F; Mon, 6 May 2019 14:43:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557153807; bh=9gbumceD6ikjDbZK1PP/dlsoDdVo2qH76kCkoJBKes8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nRcUnufjZDaSHLUyMxAIEfrlNL/3fCuVrPtx4tLfpKpm0WBazW5hW3dJ08iFUxU7e SrELkdwKMAdqEMJmKDY3UGAQbWvDWZ1evlos2bAKSl292QyQ8ICWm+QxtJLjzNMlLH 5LUw0ehbqRpViMZ/l3fYpPrF0owzQeZUAi6N2gec= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qian Cai , Borislav Petkov , Catalin Marinas , Andy Lutomirski , Brijesh Singh , Dave Hansen , "H. Peter Anvin" , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , x86-ml Subject: [PATCH 4.19 96/99] x86/mm: Fix a crash with kmemleak_scan() Date: Mon, 6 May 2019 16:33:09 +0200 Message-Id: <20190506143102.536637385@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190506143053.899356316@linuxfoundation.org> References: <20190506143053.899356316@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Qian Cai commit 0d02113b31b2017dd349ec9df2314e798a90fa6e upstream. The first kmemleak_scan() call after boot would trigger the crash below because this callpath: kernel_init free_initmem mem_encrypt_free_decrypted_mem free_init_pages unmaps memory inside the .bss when DEBUG_PAGEALLOC=y. kmemleak_init() will register the .data/.bss sections and then kmemleak_scan() will scan those addresses and dereference them looking for pointer references. If free_init_pages() frees and unmaps pages in those sections, kmemleak_scan() will crash if referencing one of those addresses: BUG: unable to handle kernel paging request at ffffffffbd402000 CPU: 12 PID: 325 Comm: kmemleak Not tainted 5.1.0-rc4+ #4 RIP: 0010:scan_block Call Trace: scan_gray_list kmemleak_scan kmemleak_scan_thread kthread ret_from_fork Since kmemleak_free_part() is tolerant to unknown objects (not tracked by kmemleak), it is fine to call it from free_init_pages() even if not all address ranges passed to this function are known to kmemleak. [ bp: Massage. ] Fixes: b3f0907c71e0 ("x86/mm: Add .bss..decrypted section to hold shared variables") Signed-off-by: Qian Cai Signed-off-by: Borislav Petkov Reviewed-by: Catalin Marinas Cc: Andy Lutomirski Cc: Brijesh Singh Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20190423165811.36699-1-cai@lca.pw Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/init.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -6,6 +6,7 @@ #include /* for max_low_pfn */ #include #include +#include #include #include @@ -767,6 +768,11 @@ void free_init_pages(char *what, unsigne if (debug_pagealloc_enabled()) { pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n", begin, end - 1); + /* + * Inform kmemleak about the hole in the memory since the + * corresponding pages will be unmapped. + */ + kmemleak_free_part((void *)begin, end - begin); set_memory_np(begin, (end - begin) >> PAGE_SHIFT); } else { /*