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Commit aba91595 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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tracing/kprobes: Fix handling of argument names 



Set "argN" name for each argument automatically if it has no specified name.
Since dynamic trace event(kprobe_events) accepts special characters for its
argument, its format can show those special characters (e.g. '$', '%', '+').
However, perf can't parse those format because of the character (especially
'%') mess up the format.  This sets "argX" name for those arguments if user
omitted the argument names.

E.g.
 # echo 'p do_fork %ax IP=%ip $stack' > tracing/kprobe_events
 # cat tracing/kprobe_events
 p:kprobes/p_do_fork_0 do_fork arg1=%ax IP=%ip arg3=$stack

Reported-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
LKML-Reference: <20100827113906.22882.59312.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 367e94c1

kernel/trace/trace_kprobe.c

+10 −7
Original line number Diff line number Diff line
@@ -997,15 +997,18 @@ static int create_trace_probe(int argc, char **argv) 


		/* Parse argument name */

		arg = strchr(argv[i], '=');

		if (arg)

		if (arg) {

			*arg++ = '\0';

		else

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

		} else {

			arg = argv[i];

			/* If argument name is omitted, set "argN" */

			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);

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

		}



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

		if (!tp->args[i].name) {

			pr_info("Failed to allocate argument%d name '%s'.\n",

				i, argv[i]);

			pr_info("Failed to allocate argument[%d] name.\n", i);

			ret = -ENOMEM;

			goto error;

		}
@@ -1014,7 +1017,7 @@ static int create_trace_probe(int argc, char **argv) 
			*tmp = '_';	/* convert : to _ */



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

			pr_info("Argument%d name '%s' conflicts with "

			pr_info("Argument[%d] name '%s' conflicts with "

				"another field.\n", i, argv[i]);

			ret = -EINVAL;

			goto error;
@@ -1023,7 +1026,7 @@ static int create_trace_probe(int argc, char **argv) 
		/* Parse fetch argument */

		ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);

		if (ret) {

			pr_info("Parse error at argument%d. (%d)\n", i, ret);

			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);

			goto error;

		}

	}