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tracing: Remove size restriction on hist trigger cmd error logging

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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: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Tom Zanussi 2022-01-28 14:08:26 -06:00 committed by Steven Rostedt (Google)
parent 1581a884b7
commit edfeed318d
1 changed files with 23 additions and 7 deletions
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30
kernel/trace/trace_events_hist.c
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@ -727,11 +727,16 @@ static struct track_data *track_data_alloc(unsigned int key_len,
return data; 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 char last_cmd_loc[MAX_FILTER_STR_VAL];
static int errpos(char *str) static int errpos(char *str)
{ {
if (!str || !last_cmd)
return 0;
return err_pos(last_cmd, str); 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; const char *system = NULL, *name = NULL;
struct trace_event_call *call; struct trace_event_call *call;
int len = 0;
if (!str) if (!str)
return; return;
strcpy(last_cmd, "hist:"); len += sizeof(HIST_PREFIX) + strlen(str) + 1;
strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1 - sizeof("hist:")); 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) { if (file) {
call = file->event_call; call = file->event_call;
@ -757,18 +769,22 @@ static void last_cmd_set(struct trace_event_file *file, char *str)
} }
if (system) 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, tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
err_type, err_pos); err_type, err_pos);
} }
static void hist_err_clear(void) static void hist_err_clear(void)
{ {
last_cmd[0] = '\0'; if (last_cmd)
last_cmd[0] = '\0';
last_cmd_loc[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; bool have_var = false;
unsigned int i; unsigned int i;
seq_puts(m, "hist:"); seq_puts(m, HIST_PREFIX);
if (data->name) if (data->name)
seq_printf(m, "%s:", data->name); seq_printf(m, "%s:", data->name);