Commit edfeed31 authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (Google)
Browse files

tracing: Remove size restriction on hist trigger cmd error logging 

Currently, hist trigger command error strings are restricted to a
length of MAX_FILTER_STR_VAL (256), which is too short for some
commands already seen in the wild (with cmd strings longer than that
showing up truncated in err_log).

Remove the restriction so that no hist trigger command error string is
ever truncated.

Link: https://lkml.kernel.org/r/0f9d46407222eaf6632cd3b417bc50a11f401b71.1643399022.git.zanussi@kernel.org



Signed-off-by: default avatarTom Zanussi <zanussi@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 1581a884

kernel/trace/trace_events_hist.c

+23 −7
Original line number Diff line number Diff line
@@ -727,11 +727,16 @@ static struct track_data *track_data_alloc(unsigned int key_len, 
	return data;

}



static char last_cmd[MAX_FILTER_STR_VAL];

#define HIST_PREFIX "hist:"



static char *last_cmd;

static char last_cmd_loc[MAX_FILTER_STR_VAL];



static int errpos(char *str)

{

	if (!str || !last_cmd)

		return 0;



	return err_pos(last_cmd, str);

}
@@ -739,12 +744,19 @@ static void last_cmd_set(struct trace_event_file *file, char *str) 
{

	const char *system = NULL, *name = NULL;

	struct trace_event_call *call;

	int len = 0;



	if (!str)

		return;



	strcpy(last_cmd, "hist:");

	strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1 - sizeof("hist:"));

	len += sizeof(HIST_PREFIX) + strlen(str) + 1;

	kfree(last_cmd);

	last_cmd = kzalloc(len, GFP_KERNEL);

	if (!last_cmd)

		return;



	strcpy(last_cmd, HIST_PREFIX);

	strncat(last_cmd, str, len - sizeof(HIST_PREFIX));



	if (file) {

		call = file->event_call;
@@ -757,17 +769,21 @@ static void last_cmd_set(struct trace_event_file *file, char *str) 
	}



	if (system)

		snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, "hist:%s:%s", system, name);

		snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name);

}



static void hist_err(struct trace_array *tr, u8 err_type, u8 err_pos)

static void hist_err(struct trace_array *tr, u8 err_type, u16 err_pos)

{

	if (!last_cmd)

		return;



	tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,

			err_type, err_pos);

}



static void hist_err_clear(void)

{

	if (last_cmd)

		last_cmd[0] = '\0';

	last_cmd_loc[0] = '\0';

}
@@ -5610,7 +5626,7 @@ static int event_hist_trigger_print(struct seq_file *m, 
	bool have_var = false;

	unsigned int i;



	seq_puts(m, "hist:");

	seq_puts(m, HIST_PREFIX);



	if (data->name)

		seq_printf(m, "%s:", data->name);