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-rw-r--r--kernel/trace/trace_events_filter.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index e1c818dbc0d7..893a206bcba4 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -78,7 +78,8 @@ static const char * ops[] = { OPS };
C(TOO_MANY_PREDS, "Too many terms in predicate expression"), \
C(INVALID_FILTER, "Meaningless filter expression"), \
C(IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \
- C(INVALID_VALUE, "Invalid value (did you forget quotes)?"),
+ C(INVALID_VALUE, "Invalid value (did you forget quotes)?"), \
+ C(NO_FILTER, "No filter found"),
#undef C
#define C(a, b) FILT_ERR_##a
@@ -550,6 +551,13 @@ predicate_parse(const char *str, int nr_parens, int nr_preds,
goto out_free;
}
+ if (!N) {
+ /* No program? */
+ ret = -EINVAL;
+ parse_error(pe, FILT_ERR_NO_FILTER, ptr - str);
+ goto out_free;
+ }
+
prog[N].pred = NULL; /* #13 */
prog[N].target = 1; /* TRUE */
prog[N+1].pred = NULL;
@@ -1693,6 +1701,7 @@ static void create_filter_finish(struct filter_parse_error *pe)
* @filter_str: filter string
* @set_str: remember @filter_str and enable detailed error in filter
* @filterp: out param for created filter (always updated on return)
+ * Must be a pointer that references a NULL pointer.
*
* Creates a filter for @call with @filter_str. If @set_str is %true,
* @filter_str is copied and recorded in the new filter.
@@ -1710,6 +1719,10 @@ static int create_filter(struct trace_event_call *call,
struct filter_parse_error *pe = NULL;
int err;
+ /* filterp must point to NULL */
+ if (WARN_ON(*filterp))
+ *filterp = NULL;
+
err = create_filter_start(filter_string, set_str, &pe, filterp);
if (err)
return err;