From 81a59555ff1593642824414267e1859024bd0162 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Sat, 11 Jan 2020 01:06:29 +0900 Subject: [PATCH] tracing/boot: Add per-event settings Add per-event settings for boottime tracing. User can set filter, actions and enable on each event on boot. The event entries are under ftrace.event.GROUP.EVENT node (note that the option key includes event's group name and event name.) This supports below configs. - ftrace.event.GROUP.EVENT.enable Enables GROUP:EVENT tracing. - ftrace.event.GROUP.EVENT.filter = FILTER Set FILTER rule to the GROUP:EVENT. - ftrace.event.GROUP.EVENT.actions = ACTION[, ACTION2...] Set ACTIONs to the GROUP:EVENT. For example, ftrace.event.sched.sched_process_exec { filter = "pid < 128" enable } this will enable tracing "sched:sched_process_exec" event with "pid < 128" filter. Link: http://lkml.kernel.org/r/157867238942.17873.11177628789184546198.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_boot.c | 60 +++++++++++++++++++++++++++++ kernel/trace/trace_events_trigger.c | 2 +- 2 files changed, 61 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 4b41310184dff9..37524031533e1f 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -56,6 +56,7 @@ trace_boot_set_ftrace_options(struct trace_array *tr, struct xbc_node *node) #ifdef CONFIG_EVENT_TRACING extern int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set); +extern int trigger_process_regex(struct trace_event_file *file, char *buff); static void __init trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node) @@ -74,8 +75,66 @@ trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node) pr_err("Failed to enable event: %s\n", p); } } + +static void __init +trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode, + struct xbc_node *enode) +{ + struct trace_event_file *file; + struct xbc_node *anode; + char buf[MAX_BUF_LEN]; + const char *p, *group, *event; + + group = xbc_node_get_data(gnode); + event = xbc_node_get_data(enode); + + mutex_lock(&event_mutex); + file = find_event_file(tr, group, event); + if (!file) { + pr_err("Failed to find event: %s:%s\n", group, event); + goto out; + } + + p = xbc_node_find_value(enode, "filter", NULL); + if (p && *p != '\0') { + if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) + pr_err("filter string is too long: %s\n", p); + else if (apply_event_filter(file, buf) < 0) + pr_err("Failed to apply filter: %s\n", buf); + } + + xbc_node_for_each_array_value(enode, "actions", anode, p) { + if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) + pr_err("action string is too long: %s\n", p); + else if (trigger_process_regex(file, buf) < 0) + pr_err("Failed to apply an action: %s\n", buf); + } + + if (xbc_node_find_value(enode, "enable", NULL)) { + if (trace_event_enable_disable(file, 1, 0) < 0) + pr_err("Failed to enable event node: %s:%s\n", + group, event); + } +out: + mutex_unlock(&event_mutex); +} + +static void __init +trace_boot_init_events(struct trace_array *tr, struct xbc_node *node) +{ + struct xbc_node *gnode, *enode; + + node = xbc_node_find_child(node, "event"); + if (!node) + return; + /* per-event key starts with "event.GROUP.EVENT" */ + xbc_node_for_each_child(node, gnode) + xbc_node_for_each_child(gnode, enode) + trace_boot_init_one_event(tr, gnode, enode); +} #else #define trace_boot_enable_events(tr, node) do {} while (0) +#define trace_boot_init_events(tr, node) do {} while (0) #endif static void __init @@ -104,6 +163,7 @@ static int __init trace_boot_init(void) return 0; trace_boot_set_ftrace_options(tr, trace_node); + trace_boot_init_events(tr, trace_node); trace_boot_enable_events(tr, trace_node); trace_boot_enable_tracer(tr, trace_node); diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 2cd53ca21b515f..d8ada4c6f3f7c2 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -213,7 +213,7 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file) return ret; } -static int trigger_process_regex(struct trace_event_file *file, char *buff) +int trigger_process_regex(struct trace_event_file *file, char *buff) { char *command, *next = buff; struct event_command *p;