[PATCH v2 2/3] tracing: Check keys for variable references in expressions too

From: Tom Zanussi
Date: Thu Apr 18 2019 - 11:19:24 EST


From: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>

There's an existing check for variable references in keys, but it
doesn't go far enough. It checks whether a key field is a variable
reference but doesn't check whether it's an expression containing
variable references, which can cause the same problems for callers.

Use the existing field_has_hist_vars() function rather than a direct
top-level flag check to catch all possible variable references.

Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Reported-by: Vincent Bernat <vincent@xxxxxxxxx>
---
kernel/trace/trace_events_hist.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 453f51ef83ca..cb56c7c456fa 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -59,7 +59,7 @@
C(NO_CLOSING_PAREN, "No closing paren found"), \
C(SUBSYS_NOT_FOUND, "Missing subsystem"), \
C(INVALID_SUBSYS_EVENT, "Invalid subsystem or event name"), \
- C(INVALID_REF_KEY, "Using variable references as keys not supported"), \
+ C(INVALID_REF_KEY, "Using variable references in keys not supported"), \
C(VAR_NOT_FOUND, "Couldn't find variable"), \
C(FIELD_NOT_FOUND, "Couldn't find field"),

@@ -4506,7 +4506,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
goto out;
}

- if (hist_field->flags & HIST_FIELD_FL_VAR_REF) {
+ if (field_has_hist_vars(hist_field, 0)) {
hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
destroy_hist_field(hist_field, 0);
ret = -EINVAL;
--
2.14.1