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tracing/boot Add kprobe event support

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Add kprobe event support on event node to boot-time tracing.
If the group name of event is "kprobes", the boot-time tracing
defines new probe event according to "probes" values.

 - ftrace.event.kprobes.EVENT.probes = PROBE[, PROBE2...]
   Defines new kprobe event based on PROBEs. It is able to define
   multiple probes on one event, but those must have same type of
   arguments.

For example,

 ftrace.events.kprobes.myevent {
	probes = "vfs_read $arg1 $arg2";
	enable;
 }

This will add kprobes:myevent on vfs_read with the 1st and the 2nd
arguments.

Link: http://lkml.kernel.org/r/157867240104.17873.9712052065426433111.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 2020-01-11 01:06:41 +09:00 committed by Steven Rostedt (VMware)
parent 81a59555ff
commit 4d655281eb
2 changed files with 51 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

46
kernel/trace/trace_boot.c
View file

@ -76,6 +76,48 @@ trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
}
}
#ifdef CONFIG_KPROBE_EVENTS
extern int trace_kprobe_run_command(const char *command);
static int __init
trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
{
struct xbc_node *anode;
char buf[MAX_BUF_LEN];
const char *val;
char *p;
int len;
len = snprintf(buf, ARRAY_SIZE(buf) - 1, "p:kprobes/%s ", event);
if (len >= ARRAY_SIZE(buf)) {
pr_err("Event name is too long: %s\n", event);
return -E2BIG;
}
p = buf + len;
len = ARRAY_SIZE(buf) - len;
xbc_node_for_each_array_value(node, "probes", anode, val) {
if (strlcpy(p, val, len) >= len) {
pr_err("Probe definition is too long: %s\n", val);
return -E2BIG;
}
if (trace_kprobe_run_command(buf) < 0) {
pr_err("Failed to add probe: %s\n", buf);
return -EINVAL;
}
}
return 0;
}
#else
static inline int __init
trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
{
pr_err("Kprobe event is not supported.\n");
return -ENOTSUPP;
}
#endif
static void __init
trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
struct xbc_node *enode)
@ -88,6 +130,10 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
group = xbc_node_get_data(gnode);
event = xbc_node_get_data(enode);
if (!strcmp(group, "kprobes"))
if (trace_boot_add_kprobe_event(enode, event) < 0)
return;
mutex_lock(&event_mutex);
file = find_event_file(tr, group, event);
if (!file) {

5
kernel/trace/trace_kprobe.c
View file

@ -902,6 +902,11 @@ static int create_or_delete_trace_kprobe(int argc, char **argv)
return ret == -ECANCELED ? -EINVAL : ret;
}
int trace_kprobe_run_command(const char *command)
{
return trace_run_command(command, create_or_delete_trace_kprobe);
}
static int trace_kprobe_release(struct dyn_event *ev)
{
struct trace_kprobe *tk = to_trace_kprobe(ev);