From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030564AbbKDPb0 (ORCPT ); Wed, 4 Nov 2015 10:31:26 -0500 Received: from mail.kernel.org ([198.145.29.136]:37699 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030404AbbKDPaU (ORCPT ); Wed, 4 Nov 2015 10:30:20 -0500 Message-Id: <20151104153013.084046678@goodmis.org> User-Agent: quilt/0.61-1 Date: Wed, 04 Nov 2015 10:29:46 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Jiaxing Wang Subject: [for-next][PATCH 12/13] tracing: Apply tracer specific options from kernel command line. References: <20151104152934.825847519@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0012-tracing-Apply-tracer-specific-options-from-kernel-co.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiaxing Wang Currently, the trace_options parameter is only applied in tracer_alloc_buffers() when global_trace.current_trace is nop_trace, so a tracer specific option will not be applied even when the specific tracer is also enabled from kernel command line. For example, the 'func_stack_trace' option can't be enabled with the following kernel parameter: ftrace=function ftrace_filter=kfree trace_options=func_stack_trace We can enable tracer specific options by simply apply the options again if the specific tracer is also supplied from command line and started in register_tracer(). To make trace_boot_options_buf can be parsed again, a comma and a space is put back if they were replaced by strsep and strstrip respectively. Also make register_tracer() be __init to access the __init data, and in fact register_tracer is only called from __init code. Link: http://lkml.kernel.org/r/1446599669-9294-1-git-send-email-hello.wjx@gmail.com Signed-off-by: Jiaxing Wang Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 45 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 9 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6459e141aac3..7fe7cc987dab 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -214,12 +214,10 @@ __setup("alloc_snapshot", boot_alloc_snapshot); static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; -static char *trace_boot_options __initdata; static int __init set_trace_boot_options(char *str) { strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE); - trace_boot_options = trace_boot_options_buf; return 0; } __setup("trace_options=", set_trace_boot_options); @@ -1223,13 +1221,15 @@ static inline int run_tracer_selftest(struct tracer *type) static void add_tracer_options(struct trace_array *tr, struct tracer *t); +static void __init apply_trace_boot_options(void); + /** * register_tracer - register a tracer with the ftrace system. * @type - the plugin for the tracer * * Register a new plugin tracer. */ -int register_tracer(struct tracer *type) +int __init register_tracer(struct tracer *type) { struct tracer *t; int ret = 0; @@ -1288,6 +1288,9 @@ int register_tracer(struct tracer *type) /* Do we want this tracer to start on bootup? */ tracing_set_tracer(&global_trace, type->name); default_bootup_tracer = NULL; + + apply_trace_boot_options(); + /* disable other selftests, since this will break it. */ tracing_selftest_disabled = true; #ifdef CONFIG_FTRACE_STARTUP_TEST @@ -3589,6 +3592,7 @@ static int trace_set_options(struct trace_array *tr, char *option) int neg = 0; int ret = -ENODEV; int i; + size_t orig_len = strlen(option); cmp = strstrip(option); @@ -3612,9 +3616,37 @@ static int trace_set_options(struct trace_array *tr, char *option) mutex_unlock(&trace_types_lock); + /* + * If the first trailing whitespace is replaced with '\0' by strstrip, + * turn it back into a space. + */ + if (orig_len > strlen(option)) + option[strlen(option)] = ' '; + return ret; } +static void __init apply_trace_boot_options(void) +{ + char *buf = trace_boot_options_buf; + char *option; + + while (true) { + option = strsep(&buf, ","); + + if (!option) + break; + if (!*option) + continue; + + trace_set_options(&global_trace, option); + + /* Put back the comma to allow this to be called again */ + if (buf) + *(buf - 1) = ','; + } +} + static ssize_t tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) @@ -7248,12 +7280,7 @@ __init static int tracer_alloc_buffers(void) INIT_LIST_HEAD(&global_trace.events); list_add(&global_trace.list, &ftrace_trace_arrays); - while (trace_boot_options) { - char *option; - - option = strsep(&trace_boot_options, ","); - trace_set_options(&global_trace, option); - } + apply_trace_boot_options(); register_snapshot_cmd(); -- 2.6.1