[PATCH 4/8] rtla/osnoise_hist: Fix segmentation fault when failing to enable -t

From: Daniel Bristot de Oliveira
Date: Mon Jan 24 2022 - 09:24:48 EST


rtla osnoise hist is causing a segmentation fault when running with
the --trace option on a kernel that does not support multiple
instances. For example:

[root@f34 rtla]# rtla osnoise hist -t daniel -s 10
failed to enable the tracer osnoise
Could not enable osnoiser tracer for tracing
Failed to enable the trace instance
Segmentation fault (core dumped)

This error happens because the exit code of the tools is trying
to destroy the trace instance that failed to be created.

Rearrange the order in which trace instances are destroyed to avoid
this problem.

Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode")
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-trace-devel@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
---
tools/tracing/rtla/src/osnoise_hist.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src/osnoise_hist.c
index 180fcbe423cd..60bf3bb4c460 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c
@@ -768,7 +768,7 @@ int osnoise_hist_main(int argc, char *argv[])
trace);
if (retval < 0) {
err_msg("Error iterating on events\n");
- goto out_hist;
+ goto out_trace;
}

if (!tracefs_trace_is_on(trace->inst))
@@ -789,12 +789,13 @@ int osnoise_hist_main(int argc, char *argv[])
}
}

+out_trace:
+ if (params->trace_output)
+ osnoise_destroy_tool(record);
out_hist:
osnoise_free_histogram(tool->data);
out_destroy:
osnoise_destroy_tool(tool);
- if (params->trace_output)
- osnoise_destroy_tool(record);
free(params);
out_exit:
exit(return_value);
--
2.34.1