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=-26.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 C64AEC4160E for ; Mon, 15 Mar 2021 16:59:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A76A96157F for ; Mon, 15 Mar 2021 16:59:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234703AbhCOQ6s (ORCPT ); Mon, 15 Mar 2021 12:58:48 -0400 Received: from linux.microsoft.com ([13.77.154.182]:51106 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234589AbhCOQ6S (ORCPT ); Mon, 15 Mar 2021 12:58:18 -0400 Received: from x64host.home (unknown [47.187.194.202]) by linux.microsoft.com (Postfix) with ESMTPSA id 342EA20B24E6; Mon, 15 Mar 2021 09:58:17 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 342EA20B24E6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1615827497; bh=NS3hnkt5UwYxkTgE05jIzpsdhEjTfgYuj02sn7S/gpA=; h=From:To:Subject:Date:In-Reply-To:References:From; b=tAnL8saAEHYVh93a0MZLgmdvKOze1VnSLCDAbic/wGmkeCijxnPAq5lTPrRz8Ym2d vNKgQxWEXET4xIPrffDDVSiyrv1y+QAUGA23mId8BWJX8hcAPSMFZsBdetjv8x/XZk SwRPm1jyxHk0hECp4kkPwzjDSMWfBy4P/6WwNoj0= From: madvenka@linux.microsoft.com To: broonie@kernel.org, mark.rutland@arm.com, jpoimboe@redhat.com, jthierry@redhat.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com Subject: [RFC PATCH v2 8/8] arm64: Implement arch_stack_walk_reliable() Date: Mon, 15 Mar 2021 11:58:00 -0500 Message-Id: <20210315165800.5948-9-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210315165800.5948-1-madvenka@linux.microsoft.com> References: <5997dfe8d261a3a543667b83c902883c1e4bd270> <20210315165800.5948-1-madvenka@linux.microsoft.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org From: "Madhavan T. Venkataraman" unwind_frame() already sets the reliable flag in the stack frame during a stack walk to indicate whether the stack trace is reliable or not. Implement arch_stack_walk_reliable() like arch_stack_walk() but abort the stack walk as soon as the reliable flag is set to false for any reason. Signed-off-by: Madhavan T. Venkataraman --- arch/arm64/Kconfig | 1 + arch/arm64/kernel/stacktrace.c | 35 ++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1f212b47a48a..954f60c35b26 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -167,6 +167,7 @@ config ARM64 if $(cc-option,-fpatchable-function-entry=2) select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ if DYNAMIC_FTRACE_WITH_REGS + select HAVE_RELIABLE_STACKTRACE select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_FAST_GUP select HAVE_FTRACE_MCOUNT_RECORD diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 752b77f11c61..5d15c111f3aa 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -361,4 +361,39 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, walk_stackframe(task, &frame, consume_entry, cookie); } +/* + * Walk the stack like arch_stack_walk() but stop the walk as soon as + * some unreliability is detected in the stack. + */ +int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, + void *cookie, struct task_struct *task) +{ + struct stackframe frame; + int ret = 0; + + if (task == current) { + start_backtrace(&frame, + (unsigned long)__builtin_frame_address(0), + (unsigned long)arch_stack_walk_reliable); + } else { + /* + * The task must not be running anywhere for the duration of + * arch_stack_walk_reliable(). The caller must guarantee + * this. + */ + start_backtrace(&frame, thread_saved_fp(task), + thread_saved_pc(task)); + } + + while (!ret) { + if (!frame.reliable) + return -EINVAL; + if (!consume_entry(cookie, frame.pc)) + return -EINVAL; + ret = unwind_frame(task, &frame); + } + + return ret == -ENOENT ? 0 : -EINVAL; +} + #endif -- 2.25.1