From patchwork Wed Sep 29 22:02:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 12526697 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 80706C433EF for ; Wed, 29 Sep 2021 22:03:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 645B761406 for ; Wed, 29 Sep 2021 22:03:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346590AbhI2WF2 (ORCPT ); Wed, 29 Sep 2021 18:05:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346734AbhI2WEG (ORCPT ); Wed, 29 Sep 2021 18:04:06 -0400 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FD2BC061768 for ; Wed, 29 Sep 2021 15:02:25 -0700 (PDT) Received: by mail-pf1-x42c.google.com with SMTP id q23so3137198pfs.9 for ; Wed, 29 Sep 2021 15:02:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=24HVUmck1VAppvs7Tv/9xSBlIyZfrWIg2aOoPOSGCPk=; b=Z7lHWLK+hOMb6TEvynvt5OOVH+QHo2cH2h2k1Ry8FKJTYlHQETIp6IxEc+SmF1BeTX yJOzvuRU5hMPQzdYuHJ65wJIoEZw01G5PrAIGEON27gmtBXYz/wKT09kpuwkF/QySjet PmgwVIZDx7jTYnmGY8m2xgJopVcTncBlMz/2k= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=24HVUmck1VAppvs7Tv/9xSBlIyZfrWIg2aOoPOSGCPk=; b=5b7FgG02zHOwJvL+Qj1GO/O1lOcYcog7JQhYLZrAEYVM2Yhz897DC0ISH67sc+L8d3 4OtMYvtPfpq3L660PcDoTInS08rdoU7YonkG3HYTqlBR0l6SZ8y4gN8TLV/yy+czU4c5 FQOvBZnblnxr7n0whyVNcryfFwdizPadRpbzCXIwPPvmCacrgBfOyNmoUVhjzqi1dypd jl09H3KdyEdKhF9kQ7ig+y/h3A67G0RyvjXIQ/rke21GDqj0f7hRHBE0Cyjl1CZ/YGaN ourrLPPv06B2oQT/4RdaAMU9xZ4GCvIxNrGH6e1JT9rJUkkOGn4vsBvwZhOOlQ2Pksct GvSA== X-Gm-Message-State: AOAM531KE3Vu396nJCx25M/g2BZgOD2bSNpES0XE+P+rauZ3AI69+eSS kI7+EzHVH1eU/OBpL1nKtAuraw== X-Google-Smtp-Source: ABdhPJwTXGwIeBPVP+42Jds8fbtC28D1cwIq/SGc7KPzUX4XorS7Wwdx4edKqckr5//XoxuyCbyXgQ== X-Received: by 2002:a05:6a00:1a04:b0:44b:346a:2a25 with SMTP id g4-20020a056a001a0400b0044b346a2a25mr753024pfv.59.1632952944631; Wed, 29 Sep 2021 15:02:24 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id u24sm720217pfm.81.2021.09.29.15.02.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Sep 2021 15:02:23 -0700 (PDT) From: Kees Cook To: Peter Zijlstra Cc: Kees Cook , Qi Zheng , kernel test robot , Vito Caputo , Jann Horn , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Andrew Morton , Christian Brauner , Anand K Mistry , "Kenta.Tada@sony.com" , Alexey Gladkov , =?utf-8?q?Michael_Wei=C3=9F?= , Michal Hocko , Helge Deller , "Tobin C. Harding" , Tycho Andersen , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , Mark Rutland , Jens Axboe , Stefan Metzmacher , Lai Jiangshan , Andy Lutomirski , Dave Hansen , "Eric W. Biederman" , Ohhoon Kwon , Kalesh Singh , YiFei Zhu , Josh Poimboeuf , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org, x86@kernel.org Subject: [PATCH v2 5/6] x86: Fix get_wchan() to support the ORC unwinder Date: Wed, 29 Sep 2021 15:02:17 -0700 Message-Id: <20210929220218.691419-6-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210929220218.691419-1-keescook@chromium.org> References: <20210929220218.691419-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2627; i=keescook@chromium.org; h=from:subject; bh=Q52zDV9YajI3kkCmjslJF3Brs06bPq6a2KD+X5RLir0=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhVOJpPZoMxuXMkWZwnGRPVVYkoF0bnz3DmLyKHCXu Uc/LlKWJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYVTiaQAKCRCJcvTf3G3AJhkJEA CSWLiYfLZArGwkCuomnnMwflTp76Al/53DgAspMiCGY+D9t1wxV/T0OQ+XuriYreg1Ob4OTVbSc7Ai MIFwyTGivV6BZBrE8hrDHjIUqcuKSeX4OU8TW9mDA79zmYv3etEQtpaliZi9F3ib9JuVjOJUKxBXly NXBX9p6RRX5RuxkNaiWIe1fiQfx4mF6ngBP+kyX40O6ZiIfnycCs6M9fqnaMf29HacI1kGKmfXieIL eZCQGdWLmGBwAaqhzhBcsPkPoCRmD+Z6NXu0xcwg7UeCQ2iwEOfdauHk/jIhQBy6eQ2ulLTqKHEFqV 22syyb7kEo3Nd0KxZGwIlLBko8LvmTaTgxNkOWSWBEycJgFO4z1myxXJath5y8VAxxJ9VL5VYQcE5E Rvi0MmCFsX1m9uW9jbtc8KHyJCH+Vosizn748Dgw/qV71Gb9cELpPnhe+qQxDw6kbw1/cklbxXc5n1 YrmgxCiKjSK6IAEcgHRKx/gQl/erbweNjGqeveXvp4hkKYd9YdLhRVVVeodSH32F105/S7GbYXGdzn NtN1ijRVXePtNwpGATDj8mNZfPIVZWevD0LHAFv1SnqnN2Y8yXFQx1bqThDITEct88Cuxujc2H7/kl bkSfx/sgrTI0SMpE9A+H4LKkTmQ1xD+aPxQ47C/a6x/lxMtP7AGoPiRrASmg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 Link: https://lore.kernel.org/r/20210831083625.59554-1-zhengqi.arch@bytedance.com --- arch/x86/kernel/process.c | 51 +++------------------------------------ 1 file changed, 3 insertions(+), 48 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 1d9463e3096b..e645925f9f02 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -944,58 +944,13 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) */ 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,