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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no 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 2054CC33CB2 for ; Fri, 31 Jan 2020 06:17:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CA5412173E for ; Fri, 31 Jan 2020 06:17:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="W9Cyee+q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA5412173E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6F2D66B05A7; Fri, 31 Jan 2020 01:17:37 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6A3816B05A9; Fri, 31 Jan 2020 01:17:37 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5B8406B05AA; Fri, 31 Jan 2020 01:17:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0115.hostedemail.com [216.40.44.115]) by kanga.kvack.org (Postfix) with ESMTP id 453E46B05A7 for ; Fri, 31 Jan 2020 01:17:37 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id E3128441A for ; Fri, 31 Jan 2020 06:17:36 +0000 (UTC) X-FDA: 76436922912.01.hill04_427123110c50c X-HE-Tag: hill04_427123110c50c X-Filterd-Recvd-Size: 3952 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jan 2020 06:17:36 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 8D6022082E; Fri, 31 Jan 2020 06:17:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580451455; bh=oHX7yp50sqiA90fQvylnvYfSIX3LrKIZtsM6LIhduvU=; h=Date:From:To:Subject:In-Reply-To:From; b=W9Cyee+qF+waq0vU7NsQrwqMvqgPsbyeQgrlGLQZryc1xzgVU+Uj4q9N6qi1p4VzT q5dvOtvNCwYHFfyvvU7Afiwbz2JuvFWoYRjtVpojckSYBqpjTguhF3zbT11ICPJVYl NqE7kCPVFCn5Rs5P0GGNvR4LWProwt4der7eee3o= Date: Thu, 30 Jan 2020 22:17:35 -0800 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, dvyukov@google.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 118/118] kcov: ignore fault-inject and stacktrace Message-ID: <20200131061735.RKRbBmv-Z%akpm@linux-foundation.org> In-Reply-To: <20200130221021.5f0211c56346d5485af07923@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Dmitry Vyukov Subject: kcov: ignore fault-inject and stacktrace Don't instrument 3 more files that contain debugging facilities and produce large amounts of uninteresting coverage for every syscall. The following snippets are sprinkled all over the place in kcov traces in a debugging kernel. We already try to disable instrumentation of stack unwinding code and of most debug facilities. I guess we did not use fault-inject.c at the time, and stacktrace.c was somehow missed (or something has changed in kernel/configs). This change both speeds up kcov (kernel doesn't need to store these PCs, user-space doesn't need to process them) and frees trace buffer capacity for more useful coverage. should_fail lib/fault-inject.c:149 fail_dump lib/fault-inject.c:45 stack_trace_save kernel/stacktrace.c:124 stack_trace_consume_entry kernel/stacktrace.c:86 stack_trace_consume_entry kernel/stacktrace.c:89 ... a hundred frames skipped ... stack_trace_consume_entry kernel/stacktrace.c:93 stack_trace_consume_entry kernel/stacktrace.c:86 Link: http://lkml.kernel.org/r/20200116111449.217744-1-dvyukov@gmail.com Signed-off-by: Dmitry Vyukov Reviewed-by: Andrey Konovalov Signed-off-by: Andrew Morton --- kernel/Makefile | 1 + lib/Makefile | 1 + mm/Makefile | 1 + 3 files changed, 3 insertions(+) --- a/kernel/Makefile~kcov-ignore-fault-inject-and-stacktrace +++ a/kernel/Makefile @@ -27,6 +27,7 @@ KCOV_INSTRUMENT_softirq.o := n # and produce insane amounts of uninteresting coverage. KCOV_INSTRUMENT_module.o := n KCOV_INSTRUMENT_extable.o := n +KCOV_INSTRUMENT_stacktrace.o := n # Don't self-instrument. KCOV_INSTRUMENT_kcov.o := n KASAN_SANITIZE_kcov.o := n --- a/lib/Makefile~kcov-ignore-fault-inject-and-stacktrace +++ a/lib/Makefile @@ -16,6 +16,7 @@ KCOV_INSTRUMENT_rbtree.o := n KCOV_INSTRUMENT_list_debug.o := n KCOV_INSTRUMENT_debugobjects.o := n KCOV_INSTRUMENT_dynamic_debug.o := n +KCOV_INSTRUMENT_fault-inject.o := n # Early boot use of cmdline, don't instrument it ifdef CONFIG_AMD_MEM_ENCRYPT --- a/mm/Makefile~kcov-ignore-fault-inject-and-stacktrace +++ a/mm/Makefile @@ -20,6 +20,7 @@ KCOV_INSTRUMENT_kmemleak.o := n KCOV_INSTRUMENT_memcontrol.o := n KCOV_INSTRUMENT_mmzone.o := n KCOV_INSTRUMENT_vmstat.o := n +KCOV_INSTRUMENT_failslab.o := n CFLAGS_init-mm.o += $(call cc-disable-warning, override-init) CFLAGS_init-mm.o += $(call cc-disable-warning, initializer-overrides) _