From patchwork Fri Oct 8 11:15:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545017 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E1DAC433F5 for ; Fri, 8 Oct 2021 11:17:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2456961029 for ; Fri, 8 Oct 2021 11:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240084AbhJHLTW (ORCPT ); Fri, 8 Oct 2021 07:19:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240122AbhJHLTK (ORCPT ); Fri, 8 Oct 2021 07:19:10 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B58D7C061764; Fri, 8 Oct 2021 04:17:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=xqtSQc07C3rrqTOXV9I/wLRnSKhuTNgADm5tRsfdrx4=; b=jdp2wcmqAFjAKRQTb13W/FfcbX 5THzVflwDLXHmU+1VHlpGnNzTlDcWbP5Bbhlrn2dMaahApt3v59WDJpUN2/Shz2Y4uzMtzIZ/3GTf NIAcpWAqZR4cZjsdrV3CDr0gSgHyhXLcBF8/GnXXvLw1VOmhRxvpKLSa1KrJTHsRZA7hBrkRWQtbo 2fI1bGOYfoMVgGstcikreGv6tYHZ8JRV5FEEdPt6KH+8bDOlws3gc4nVReriuWNcdJtbzSPOE44gI LKwKme969M29j7+Y8UsAj+oo24GOI+8jgA8Av9uVjk/67iNtB9Zc0QnPtn6j8sGvp95ZSHFUDzcWw r/Gz8pOA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYnsD-008eLC-AT; Fri, 08 Oct 2021 11:17:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A61EF302D3A; Fri, 8 Oct 2021 13:17:08 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id E0CCF2DB84A69; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.271115116@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:31 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 4/7] x86: Fix get_wchan() to support the ORC unwinder References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Qi Zheng Currently, the kernel CONFIG_UNWINDER_ORC option is enabled by default on x86, but the implementation of get_wchan() is still based on the frame pointer unwinder, so the /proc//wchan usually returned 0 regardless of whether the task is running. Reimplement get_wchan() by calling stack_trace_save_tsk(), which is adapted to the ORC and frame pointer unwinders. Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Signed-off-by: Qi Zheng Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/kernel/process.c | 51 ++-------------------------------------------- 1 file changed, 3 insertions(+), 48 deletions(-) --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -944,58 +944,13 @@ unsigned long arch_randomize_brk(struct */ unsigned long get_wchan(struct task_struct *p) { - unsigned long start, bottom, top, sp, fp, ip, ret = 0; - int count = 0; + unsigned long entry = 0; if (p == current || task_is_running(p)) return 0; - if (!try_get_task_stack(p)) - return 0; - - start = (unsigned long)task_stack_page(p); - if (!start) - goto out; - - /* - * Layout of the stack page: - * - * ----------- topmax = start + THREAD_SIZE - sizeof(unsigned long) - * PADDING - * ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING - * stack - * ----------- bottom = start - * - * The tasks stack pointer points at the location where the - * framepointer is stored. The data on the stack is: - * ... IP FP ... IP FP - * - * We need to read FP and IP, so we need to adjust the upper - * bound by another unsigned long. - */ - top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING; - top -= 2 * sizeof(unsigned long); - bottom = start; - - sp = READ_ONCE(p->thread.sp); - if (sp < bottom || sp > top) - goto out; - - fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp); - do { - if (fp < bottom || fp > top) - goto out; - ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long))); - if (!in_sched_functions(ip)) { - ret = ip; - goto out; - } - fp = READ_ONCE_NOCHECK(*(unsigned long *)fp); - } while (count++ < 16 && !task_is_running(p)); - -out: - put_task_stack(p); - return ret; + stack_trace_save_tsk(p, &entry, 1, 0); + return entry; } long do_arch_prctl_common(struct task_struct *task, int option,