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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 75C32C10F27 for ; Mon, 9 Mar 2020 19:06:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A46320637 for ; Mon, 9 Mar 2020 19:06:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583780768; bh=I804D6YeTMRsH5LhBhkAVlRExqjQXEXDuOOvt4CWa38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hKdQPmor+oVYjICt8ao8S83uMsEIYfuk3NepaDoG5yqf7e7QqQqpF1BiP//wTpwDq MjDdrMhNx0JBt02uCs16z3u4ZTl0N533VLgE5f6zmiwanZRBFW6djsKZa0Oiot+JoQ oRW8G3xHfQHwfh7g9eidHnRhVdMeWoJwoFMm62TM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727558AbgCITEY (ORCPT ); Mon, 9 Mar 2020 15:04:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:47544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727439AbgCITEX (ORCPT ); Mon, 9 Mar 2020 15:04:23 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5EC5B222D9; Mon, 9 Mar 2020 19:04:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583780662; bh=I804D6YeTMRsH5LhBhkAVlRExqjQXEXDuOOvt4CWa38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D/XKQ7Z0IYG4rJkvjl9tt9z1wfEkB0YUH1+QsTHywdCp5nce6/hj18ToKB53PTab2 QLEzf70d1a1bz6QAw3zEGugx35tFn5XBEiaz661t+emOEnL98amKJOA5q7IkBrSCx2 nEnNRZQNKJJnMHtFYJGXsgF2gcBrFq4LR7HJGh34= From: paulmck@kernel.org To: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, kernel-team@fb.com, mingo@kernel.org Cc: elver@google.com, andreyknvl@google.com, glider@google.com, dvyukov@google.com, cai@lca.pw, boqun.feng@gmail.com, "Paul E . McKenney" Subject: [PATCH kcsan 02/32] kcsan: Show full access type in report Date: Mon, 9 Mar 2020 12:03:50 -0700 Message-Id: <20200309190420.6100-2-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200309190359.GA5822@paulmck-ThinkPad-P72> References: <20200309190359.GA5822@paulmck-ThinkPad-P72> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marco Elver This commit adds access-type information to KCSAN's reports as follows: "read", "read (marked)", "write", and "write (marked)". Suggested-by: Paul E. McKenney Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney --- kernel/kcsan/core.c | 15 ++++++++------- kernel/kcsan/kcsan.h | 2 +- kernel/kcsan/report.c | 43 ++++++++++++++++++++++++++++--------------- 3 files changed, 37 insertions(+), 23 deletions(-) diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c index 4d4ab5c..87bf857 100644 --- a/kernel/kcsan/core.c +++ b/kernel/kcsan/core.c @@ -255,7 +255,7 @@ static inline unsigned int get_delay(void) static noinline void kcsan_found_watchpoint(const volatile void *ptr, size_t size, - bool is_write, + int type, atomic_long_t *watchpoint, long encoded_watchpoint) { @@ -276,7 +276,7 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr, flags = user_access_save(); if (consumed) { - kcsan_report(ptr, size, is_write, true, raw_smp_processor_id(), + kcsan_report(ptr, size, type, true, raw_smp_processor_id(), KCSAN_REPORT_CONSUMED_WATCHPOINT); } else { /* @@ -292,8 +292,9 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr, } static noinline void -kcsan_setup_watchpoint(const volatile void *ptr, size_t size, bool is_write) +kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type) { + const bool is_write = (type & KCSAN_ACCESS_WRITE) != 0; atomic_long_t *watchpoint; union { u8 _1; @@ -415,13 +416,13 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, bool is_write) * No need to increment 'data_races' counter, as the racing * thread already did. */ - kcsan_report(ptr, size, is_write, size > 8 || value_change, + kcsan_report(ptr, size, type, size > 8 || value_change, smp_processor_id(), KCSAN_REPORT_RACE_SIGNAL); } else if (value_change) { /* Inferring a race, since the value should not have changed. */ kcsan_counter_inc(KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN); if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN)) - kcsan_report(ptr, size, is_write, true, + kcsan_report(ptr, size, type, true, smp_processor_id(), KCSAN_REPORT_RACE_UNKNOWN_ORIGIN); } @@ -455,10 +456,10 @@ static __always_inline void check_access(const volatile void *ptr, size_t size, */ if (unlikely(watchpoint != NULL)) - kcsan_found_watchpoint(ptr, size, is_write, watchpoint, + kcsan_found_watchpoint(ptr, size, type, watchpoint, encoded_watchpoint); else if (unlikely(should_watch(ptr, type))) - kcsan_setup_watchpoint(ptr, size, is_write); + kcsan_setup_watchpoint(ptr, size, type); } /* === Public interface ===================================================== */ diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h index d3b9a96..8492da4 100644 --- a/kernel/kcsan/kcsan.h +++ b/kernel/kcsan/kcsan.h @@ -103,7 +103,7 @@ enum kcsan_report_type { /* * Print a race report from thread that encountered the race. */ -extern void kcsan_report(const volatile void *ptr, size_t size, bool is_write, +extern void kcsan_report(const volatile void *ptr, size_t size, int access_type, bool value_change, int cpu_id, enum kcsan_report_type type); #endif /* _KERNEL_KCSAN_KCSAN_H */ diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c index 0eea05a..9f503ca 100644 --- a/kernel/kcsan/report.c +++ b/kernel/kcsan/report.c @@ -24,7 +24,7 @@ static struct { const volatile void *ptr; size_t size; - bool is_write; + int access_type; int task_pid; int cpu_id; unsigned long stack_entries[NUM_STACK_ENTRIES]; @@ -41,8 +41,10 @@ static DEFINE_SPINLOCK(report_lock); * Special rules to skip reporting. */ static bool -skip_report(bool is_write, bool value_change, unsigned long top_frame) +skip_report(int access_type, bool value_change, unsigned long top_frame) { + const bool is_write = (access_type & KCSAN_ACCESS_WRITE) != 0; + if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY) && is_write && !value_change) { /* @@ -63,9 +65,20 @@ skip_report(bool is_write, bool value_change, unsigned long top_frame) return kcsan_skip_report_debugfs(top_frame); } -static inline const char *get_access_type(bool is_write) +static const char *get_access_type(int type) { - return is_write ? "write" : "read"; + switch (type) { + case 0: + return "read"; + case KCSAN_ACCESS_ATOMIC: + return "read (marked)"; + case KCSAN_ACCESS_WRITE: + return "write"; + case KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC: + return "write (marked)"; + default: + BUG(); + } } /* Return thread description: in task or interrupt. */ @@ -112,7 +125,7 @@ static int sym_strcmp(void *addr1, void *addr2) /* * Returns true if a report was generated, false otherwise. */ -static bool print_report(const volatile void *ptr, size_t size, bool is_write, +static bool print_report(const volatile void *ptr, size_t size, int access_type, bool value_change, int cpu_id, enum kcsan_report_type type) { @@ -124,7 +137,7 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write, /* * Must check report filter rules before starting to print. */ - if (skip_report(is_write, true, stack_entries[skipnr])) + if (skip_report(access_type, true, stack_entries[skipnr])) return false; if (type == KCSAN_REPORT_RACE_SIGNAL) { @@ -132,7 +145,7 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write, other_info.num_stack_entries); /* @value_change is only known for the other thread */ - if (skip_report(other_info.is_write, value_change, + if (skip_report(other_info.access_type, value_change, other_info.stack_entries[other_skipnr])) return false; } @@ -170,7 +183,7 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write, switch (type) { case KCSAN_REPORT_RACE_SIGNAL: pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n", - get_access_type(other_info.is_write), other_info.ptr, + get_access_type(other_info.access_type), other_info.ptr, other_info.size, get_thread_desc(other_info.task_pid), other_info.cpu_id); @@ -181,14 +194,14 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write, pr_err("\n"); pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n", - get_access_type(is_write), ptr, size, + get_access_type(access_type), ptr, size, get_thread_desc(in_task() ? task_pid_nr(current) : -1), cpu_id); break; case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: pr_err("race at unknown origin, with %s to 0x%px of %zu bytes by %s on cpu %i:\n", - get_access_type(is_write), ptr, size, + get_access_type(access_type), ptr, size, get_thread_desc(in_task() ? task_pid_nr(current) : -1), cpu_id); break; @@ -223,7 +236,7 @@ static void release_report(unsigned long *flags, enum kcsan_report_type type) * required for the report type, simply acquires report_lock and returns true. */ static bool prepare_report(unsigned long *flags, const volatile void *ptr, - size_t size, bool is_write, int cpu_id, + size_t size, int access_type, int cpu_id, enum kcsan_report_type type) { if (type != KCSAN_REPORT_CONSUMED_WATCHPOINT && @@ -243,7 +256,7 @@ static bool prepare_report(unsigned long *flags, const volatile void *ptr, other_info.ptr = ptr; other_info.size = size; - other_info.is_write = is_write; + other_info.access_type = access_type; other_info.task_pid = in_task() ? task_pid_nr(current) : -1; other_info.cpu_id = cpu_id; other_info.num_stack_entries = stack_trace_save(other_info.stack_entries, NUM_STACK_ENTRIES, 1); @@ -302,14 +315,14 @@ static bool prepare_report(unsigned long *flags, const volatile void *ptr, goto retry; } -void kcsan_report(const volatile void *ptr, size_t size, bool is_write, +void kcsan_report(const volatile void *ptr, size_t size, int access_type, bool value_change, int cpu_id, enum kcsan_report_type type) { unsigned long flags = 0; kcsan_disable_current(); - if (prepare_report(&flags, ptr, size, is_write, cpu_id, type)) { - if (print_report(ptr, size, is_write, value_change, cpu_id, type) && panic_on_warn) + if (prepare_report(&flags, ptr, size, access_type, cpu_id, type)) { + if (print_report(ptr, size, access_type, value_change, cpu_id, type) && panic_on_warn) panic("panic_on_warn set ...\n"); release_report(&flags, type); -- 2.9.5