[PATCH 3/9] tracing: Exclude 'generic fields' from histograms

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From	Tom Zanussi <tom.zanussi@linux.intel.com>
Newsgroups	linux.kernel
Subject	[PATCH 3/9] tracing: Exclude 'generic fields' from histograms
Date	Fri, 22 Sep 2017 22:00:02 +0200
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There are a small number of 'generic fields' (comm/COMM/cpu/CPU) that
are found by trace_find_event_field() but are only meant for
filtering.  Specifically, they unlike normal fields, they have a size
of 0 and thus wreak havoc when used as a histogram key.

Exclude these (return -EINVAL) when used as histogram keys.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 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 1c21d0e..7eb975a 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -450,7 +450,7 @@ static int create_val_field(struct hist_trigger_data *hist_data,
 	}
 
 	field = trace_find_event_field(file->event_call, field_name);
-	if (!field) {
+	if (!field || !field->size) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -548,7 +548,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
 		}
 
 		field = trace_find_event_field(file->event_call, field_name);
-		if (!field) {
+		if (!field || !field->size) {
 			ret = -EINVAL;
 			goto out;
 		}
-- 
1.9.3

Thread

[PATCH 0/9] tracing: Bug fixes and minor cleanup Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:00 +0200
  [PATCH 5/9] tracing: Increase tracing map KEYS_MAX size Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:00 +0200
  [PATCH 3/9] tracing: Exclude 'generic fields' from histograms Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:00 +0200
  [PATCH 1/9] tracing: Steve's unofficial trace_recursive_lock() patch Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:00 +0200
  [PATCH 4/9] tracing: Remove lookups from tracing_map hitcount Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:00 +0200
  [PATCH 9/9] tracing: Reimplement log2 Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:10 +0200
  [PATCH 7/9] tracing: Clean up hist_field_flags enum Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:10 +0200
  [PATCH 8/9] tracing: Add hist_field_name() accessor Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:10 +0200
  [PATCH 2/9] tracing: Reverse the order of trace_types_lock and event_mutex Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-09-22 22:20 +0200

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