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tracing/kprobe: Add kprobe_event= boot parameter

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Add kprobe_event= boot parameter to define kprobe events
at boot time.
The definition syntax is similar to tracefs/kprobe_events
interface, but use ',' and ';' instead of ' ' and '\n'
respectively. e.g.

  kprobe_event=p,vfs_read,$arg1,$arg2

This puts a probe on vfs_read with argument1 and 2, and
enable the new event.

Link: http://lkml.kernel.org/r/155851395498.15728.830529496248543583.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu
2019-05-22 17:32:35 +09:00
committed by Steven Rostedt (VMware)
parent b5f8b32c93
commit 970988e19e
3 changed files with 81 additions and 0 deletions
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54
kernel/trace/trace_kprobe.c
View File

@@ -12,6 +12,8 @@
#include <linux/rculist.h>
#include <linux/error-injection.h>
#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
#include "trace_dynevent.h"
#include "trace_kprobe_selftest.h"
#include "trace_probe.h"
@@ -19,6 +21,17 @@
#define KPROBE_EVENT_SYSTEM "kprobes"
#define KRETPROBE_MAXACTIVE_MAX 4096
#define MAX_KPROBE_CMDLINE_SIZE 1024
/* Kprobe early definition from command line */
static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
static int __init set_kprobe_boot_events(char *str)
{
strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
return 0;
}
__setup("kprobe_event=", set_kprobe_boot_events);
static int trace_kprobe_create(int argc, const char **argv);
static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
@@ -1494,6 +1507,44 @@ void destroy_local_trace_kprobe(struct trace_event_call *event_call)
}
#endif /* CONFIG_PERF_EVENTS */
static __init void enable_boot_kprobe_events(void)
{
struct trace_array *tr = top_trace_array();
struct trace_event_file *file;
struct trace_kprobe *tk;
struct dyn_event *pos;
mutex_lock(&event_mutex);
for_each_trace_kprobe(tk, pos) {
list_for_each_entry(file, &tr->events, list)
if (file->event_call == &tk->tp.call)
trace_event_enable_disable(file, 1, 0);
}
mutex_unlock(&event_mutex);
}
static __init void setup_boot_kprobe_events(void)
{
char *p, *cmd = kprobe_boot_events_buf;
int ret;
strreplace(kprobe_boot_events_buf, ',', ' ');
while (cmd && *cmd != '\0') {
p = strchr(cmd, ';');
if (p)
*p++ = '\0';
ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
if (ret)
pr_warn("Failed to add event(%d): %s\n", ret, cmd);
cmd = p;
}
enable_boot_kprobe_events();
}
/* Make a tracefs interface for controlling probe points */
static __init int init_kprobe_trace(void)
{
@@ -1525,6 +1576,9 @@ static __init int init_kprobe_trace(void)
if (!entry)
pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
setup_boot_kprobe_events();
return 0;
}
fs_initcall(init_kprobe_trace);