Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Daniel Bristot de Oliveira <bristot@kernel.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Daniel Bristot de Oliveira <bristot@kernel.org>,
        linux-kernel@vger.kernel.org, linux-trace-devel@vger.kernel.org
Subject: [PATCH 5/8] rtla/timerlat_top: Fix segmentation fault when failing to enable -t
Date:   Mon, 24 Jan 2022 15:24:08 +0100
Message-Id: <2fea7678dda97e09ef80fd5775abf51fc105a857.1643033113.git.bristot@kernel.org>
In-Reply-To: <cover.1643033113.git.bristot@kernel.org>
References: <cover.1643033113.git.bristot@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8BIT
Content-Type: text/plain; charset=WINDOWS-1252
Precedence: bulk

rtla timerlat top 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 timerlat top -t
    failed to enable the tracer timerlat
    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: a828cd18bc4a ("rtla: Add timerlat tool and timelart top mode")
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 tools/tracing/rtla/src/timerlat_top.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 1ebd5291539c..323fd1f88313 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -584,7 +584,7 @@ int timerlat_top_main(int argc, char *argv[])
 						    trace);
 		if (retval < 0) {
 			err_msg("Error iterating on events\n");
-			goto out_top;
+			goto out_trace;
 		}
 
 		if (!params->quiet)
@@ -606,12 +606,12 @@ int timerlat_top_main(int argc, char *argv[])
 			save_trace_to_file(record->trace.inst, params->trace_output);
 		}
 	}
-
+out_trace:
+	if (params->trace_output)
+		osnoise_destroy_tool(record);
 out_top:
 	timerlat_free_top(top->data);
 	osnoise_destroy_tool(top);
-	if (params->trace_output)
-		osnoise_destroy_tool(record);
 	free(params);
 out_exit:
 	exit(return_value);
-- 
2.34.1