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Subject[PATCH v2] trace-cmd record: Fix syntax in make_pid_filter
Date
In older versions of the kernel, event filtering by
pid does not use the set_event_pid file. Instead,
ftrace uses a common filter (created in make_pid_filter)
to filter events based on PID.

The syntax of the filter generated by this function is
overly permissive. When filtering by pid, || is used
where && should be (in certain cases) which means that
unrelated events are captured.

Signed-off-by: Will Hawkins <hawkinsw@borlaugic.com>
---
trace-record.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/trace-record.c b/trace-record.c
index a0b6541..741fe53 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -935,14 +935,16 @@ static char *make_pid_filter(char *curr_filter, const char *field)
str = filter + curr_len;

for (p = filter_pids; p; p = p->next) {
- if (p == filter_pids)
- orit = "";
- else
- orit = "||";
- if (p->exclude)
+ if (p->exclude) {
match = "!=";
- else
+ orit = "&&";
+ } else {
match = "==";
+ orit = "||";
+ }
+ if (p == filter_pids)
+ orit = "";
+
len = sprintf(str, "%s(%s%s%d)", orit, field, match, p->pid);
str += len;
}
--
2.7.4
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