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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 01985C33CB1 for ; Thu, 16 Jan 2020 11:14:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0C052077B for ; Thu, 16 Jan 2020 11:14:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jYfYaY1Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726535AbgAPLOz (ORCPT ); Thu, 16 Jan 2020 06:14:55 -0500 Received: from mail-wr1-f68.google.com ([209.85.221.68]:39567 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725800AbgAPLOz (ORCPT ); Thu, 16 Jan 2020 06:14:55 -0500 Received: by mail-wr1-f68.google.com with SMTP id y11so18718745wrt.6 for ; Thu, 16 Jan 2020 03:14:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=R9Q5677Ur8luUcGkjg5jrHlKUFNub/5xyB+iK5Dfa/s=; b=jYfYaY1Y6tNtnRFTCmbfc0F8+6Msw8UQArIB4KgtZVxXojOX7OKT+38UZSMgu4+9Yn xClOjGo46iBLZWRmKkPkzVe+1InGWGuhMhp4teIj0Cyn7T/ZTY9sbhLxTZMYxXLrGQ9N wb/RxUTh5u0pyfy0fzVGfAyQjlnEiqEkneEzPohuJlhhsKrUZ+9jw98Mgmp71i3Wozut /RH/skJplLqwzHY8UvJt6m/Ifhh73fMww3qDnx1wiVsZMkC0WBEobaK4InoVVQB4T3zp hm0pxGoOA/P37+fWny+NOEuiMJMjDNXK3b7zcuLaOLHAPG5xBuEaP3FWLIhrD3bkatLw ql4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=R9Q5677Ur8luUcGkjg5jrHlKUFNub/5xyB+iK5Dfa/s=; b=ffbdSRb3i88QyBm39VfQcN3CnnckS1T0cwd3k/Tq8UuIoN10rA/DwN/AgsQiPl2qIS +oQ6br+zzkxF5c1nActqkJsXV02fesTKxQKL1XHOMDTszheC7cDh4BfysOGctZgVjKou 6YKekzIzQEqa4augqXBcwwd6z+o+txJkvalPiC5KVbn1pcq/E8IHU2PKAs28VLZdn4oD B/5FwdQdeqG/P8CnjuTsVhcPiJzOywEJOproR/WxIKBbfHqp5Dtbm9aqryX908PDxIpI aPHnfT09eWvOaKQGejmIUzTzMGg+6iNqmA0+sW9Z6JIvGVYYgEDTv/0erEP0mGwQkX5r i8dQ== X-Gm-Message-State: APjAAAUGY91v4lBYst/61X0NmzYl7quWyB9fH+j5+sYKA8Q2RgpqXC9l i6QFIF3o7hzY2y13HY3CEyADOn//I6k= X-Google-Smtp-Source: APXvYqx0CXV5gVBMYwHmkz1J0LkphHRM8RPwbH6gJgYhylUNLOT9aC2Itcv3FJmB1fCRQ/q1PH9G2A== X-Received: by 2002:adf:9c8f:: with SMTP id d15mr2748995wre.390.1579173293323; Thu, 16 Jan 2020 03:14:53 -0800 (PST) Received: from dvyukov-desk.muc.corp.google.com ([2a00:79e0:15:13:aecf:473e:300f:893f]) by smtp.gmail.com with ESMTPSA id w19sm3573792wmc.22.2020.01.16.03.14.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2020 03:14:52 -0800 (PST) From: Dmitry Vyukov To: akpm@linux-foundation.org Cc: Dmitry Vyukov , Andrey Konovalov , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org Subject: [PATCH] kcov: ignore fault-inject and stacktrace Date: Thu, 16 Jan 2020 12:14:49 +0100 Message-Id: <20200116111449.217744-1-dvyukov@gmail.com> X-Mailer: git-send-email 2.25.0.rc1.283.g88dfdc4193-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitry Vyukov 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 Signed-off-by: Dmitry Vyukov Cc: Andrew Morton Cc: Andrey Konovalov Cc: kasan-dev@googlegroups.com Cc: linux-kernel@vger.kernel.org --- kernel/Makefile | 1 + lib/Makefile | 1 + mm/Makefile | 1 + 3 files changed, 3 insertions(+) diff --git a/kernel/Makefile b/kernel/Makefile index e5ffd8c002541..5d935b63f812a 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -30,6 +30,7 @@ KCSAN_SANITIZE_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 diff --git a/lib/Makefile b/lib/Makefile index 004a4642938af..6cd19bb3085c5 100644 --- a/lib/Makefile +++ b/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 diff --git a/mm/Makefile b/mm/Makefile index 3c53198835479..c9696f3ec8408 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -28,6 +28,7 @@ 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) -- 2.25.0.rc1.283.g88dfdc4193-goog