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Commit a703d946 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
Browse files

tracing/kprobes: Avoid field name confliction 



Check whether the argument name is in conflict with other field names
while creating a kprobe through the debugfs interface.

Changes in v3:
 - Check strcmp() == 0 instead of !strcmp().

Changes in v2:
 - Add common_lock_depth to reserved name list.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
LKML-Reference: <20091007222807.1684.26880.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 2e06ff63

kernel/trace/trace_kprobe.c

+53 −12
Original line number Diff line number Diff line
@@ -38,6 +38,25 @@ 
#define MAX_EVENT_NAME_LEN 64

#define KPROBE_EVENT_SYSTEM "kprobes"



/* Reserved field names */

#define FIELD_STRING_IP "ip"

#define FIELD_STRING_NARGS "nargs"

#define FIELD_STRING_RETIP "ret_ip"

#define FIELD_STRING_FUNC "func"



const char *reserved_field_names[] = {

	"common_type",

	"common_flags",

	"common_preempt_count",

	"common_pid",

	"common_tgid",

	"common_lock_depth",

	FIELD_STRING_IP,

	FIELD_STRING_NARGS,

	FIELD_STRING_RETIP,

	FIELD_STRING_FUNC,

};



/* currently, trace_kprobe only supports X86. */



struct fetch_func {
@@ -537,6 +556,20 @@ static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return) 
	return ret;

}



/* Return 1 if name is reserved or already used by another argument */

static int conflict_field_name(const char *name,

			       struct probe_arg *args, int narg)

{

	int i;

	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)

		if (strcmp(reserved_field_names[i], name) == 0)

			return 1;

	for (i = 0; i < narg; i++)

		if (strcmp(args[i].name, name) == 0)

			return 1;

	return 0;

}



static int create_trace_probe(int argc, char **argv)

{

	/*
@@ -637,6 +670,12 @@ static int create_trace_probe(int argc, char **argv) 
			*arg++ = '\0';

		else

			arg = argv[i];



		if (conflict_field_name(argv[i], tp->args, i)) {

			ret = -EINVAL;

			goto error;

		}



		tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);



		/* Parse fetch argument */
@@ -1039,8 +1078,8 @@ static int kprobe_event_define_fields(struct ftrace_event_call *event_call) 
	if (!ret)

		return ret;



	DEFINE_FIELD(unsigned long, ip, "ip", 0);

	DEFINE_FIELD(int, nargs, "nargs", 1);

	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);

	DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);

	/* Set argument names as fields */

	for (i = 0; i < tp->nr_args; i++)

		DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
@@ -1057,9 +1096,9 @@ static int kretprobe_event_define_fields(struct ftrace_event_call *event_call) 
	if (!ret)

		return ret;



	DEFINE_FIELD(unsigned long, func, "func", 0);

	DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0);

	DEFINE_FIELD(int, nargs, "nargs", 1);

	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);

	DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);

	DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);

	/* Set argument names as fields */

	for (i = 0; i < tp->nr_args; i++)

		DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
@@ -1108,15 +1147,16 @@ static int kprobe_event_show_format(struct ftrace_event_call *call, 
	int ret, i;

	struct trace_probe *tp = (struct trace_probe *)call->data;



	SHOW_FIELD(unsigned long, ip, "ip");

	SHOW_FIELD(int, nargs, "nargs");

	SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);

	SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);



	/* Show fields */

	for (i = 0; i < tp->nr_args; i++)

		SHOW_FIELD(unsigned long, args[i], tp->args[i].name);

	trace_seq_puts(s, "\n");



	return __probe_event_show_format(s, tp, "(%lx)", "REC->ip");

	return __probe_event_show_format(s, tp, "(%lx)",

					 "REC->" FIELD_STRING_IP);

}



static int kretprobe_event_show_format(struct ftrace_event_call *call,
@@ -1126,9 +1166,9 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, 
	int ret, i;

	struct trace_probe *tp = (struct trace_probe *)call->data;



	SHOW_FIELD(unsigned long, func, "func");

	SHOW_FIELD(unsigned long, ret_ip, "ret_ip");

	SHOW_FIELD(int, nargs, "nargs");

	SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);

	SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);

	SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);



	/* Show fields */

	for (i = 0; i < tp->nr_args; i++)
@@ -1136,7 +1176,8 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, 
	trace_seq_puts(s, "\n");



	return __probe_event_show_format(s, tp, "(%lx <- %lx)",

					  "REC->func, REC->ret_ip");

					 "REC->" FIELD_STRING_FUNC

					 ", REC->" FIELD_STRING_RETIP);

}



#ifdef CONFIG_EVENT_PROFILE