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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 666B9C433F5 for ; Tue, 11 Jan 2022 17:32:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344727AbiAKRb5 (ORCPT ); Tue, 11 Jan 2022 12:31:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344357AbiAKRbT (ORCPT ); Tue, 11 Jan 2022 12:31:19 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B1B1C061751 for ; Tue, 11 Jan 2022 09:31:19 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 78C50B81C3D for ; Tue, 11 Jan 2022 17:31:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4015BC36AF4; Tue, 11 Jan 2022 17:31:16 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1n7KzL-0032AT-Do; Tue, 11 Jan 2022 12:31:15 -0500 Message-ID: <20220111173115.271910572@goodmis.org> User-Agent: quilt/0.66 Date: Tue, 11 Jan 2022 12:30:42 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Yinan Liu Subject: [for-next][PATCH 11/31] ftrace: Add test to make sure compiled time sorts work References: <20220111173030.999527342@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" Now that ftrace function pointers are sorted at compile time, add a test that makes sure they are sorted at run time. This test is only run if it is configured in. Link: https://lkml.kernel.org/r/20211206151858.4d21a24d@gandalf.local.home Cc: Yinan Liu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/Kconfig | 14 ++++++++++++++ kernel/trace/ftrace.c | 23 +++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 420ff4bc67fd..f468767bc287 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -915,6 +915,20 @@ config EVENT_TRACE_TEST_SYSCALLS TBD - enable a way to actually call the syscalls as we test their events +config FTRACE_SORT_STARTUP_TEST + bool "Verify compile time sorting of ftrace functions" + depends on DYNAMIC_FTRACE + depends on BUILDTIME_TABLE_SORT + help + Sorting of the mcount_loc sections that is used to find the + where the ftrace knows where to patch functions for tracing + and other callbacks is done at compile time. But if the sort + is not done correctly, it will cause non-deterministic failures. + When this is set, the sorted sections will be verified that they + are in deed sorted and will warn if they are not. + + If unsure, say N + config RING_BUFFER_STARTUP_TEST bool "Ring buffer startup self test" depends on RING_BUFFER diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9ca63df6553a..403e485bf091 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6388,6 +6388,27 @@ static int ftrace_cmp_ips(const void *a, const void *b) return 0; } +#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST +static void test_is_sorted(unsigned long *start, unsigned long count) +{ + int i; + + for (i = 1; i < count; i++) { + if (WARN(start[i - 1] > start[i], + "[%d] %pS at %lx is not sorted with %pS at %lx\n", i, + (void *)start[i - 1], start[i - 1], + (void *)start[i], start[i])) + break; + } + if (i == count) + pr_info("ftrace section at %px sorted properly\n", start); +} +#else +static void test_is_sorted(unsigned long *start, unsigned long count) +{ +} +#endif + static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) @@ -6414,6 +6435,8 @@ static int ftrace_process_locs(struct module *mod, if (!IS_ENABLED(CONFIG_BUILDTIME_TABLE_SORT) || mod) { sort(start, count, sizeof(*start), ftrace_cmp_ips, NULL); + } else { + test_is_sorted(start, count); } start_pg = ftrace_allocate_pages(count); -- 2.33.0