From: Steven Rostedt <rostedt@xxxxxxxxxxx> Masami reported a bug when running function graph tracing then the function profiler. The following commands would cause a kernel crash: # cd /sys/kernel/tracing/ # echo function_graph > current_tracer # echo 1 > function_profile_enabled In that order. Create a test to test this two to make sure this does not come back as a regression. Link: https://lore.kernel.org/172398528350.293426.8347220120333730248.stgit@devnote2 Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> --- Changes since v2: https://lore.kernel.org/20241004145618.18436d7e@xxxxxxxxxxxxxxxxxx - Fixed grammar of comment .../ftrace/test.d/ftrace/fgraph-profiler.tc | 31 +++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/fgraph-profiler.tc diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-profiler.tc b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-profiler.tc new file mode 100644 index 000000000000..ffff8646733c --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-profiler.tc @@ -0,0 +1,31 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: ftrace - function profiler with function graph tracing +# requires: function_profile_enabled set_ftrace_filter function_graph:tracer + +# The function graph tracer can now be run along side of the function +# profiler. But there was a bug that caused the combination of the two +# to crash. It also required the function graph tracer to be started +# first. +# +# This test triggers that bug +# +# We need both function_graph and profiling to run this test + +fail() { # mesg + echo $1 + exit_fail +} + +echo "Enabling function graph tracer:" +echo function_graph > current_tracer +echo "enable profiler" + +# Older kernels do not allow function_profile to be enabled with +# function graph tracer. If the below fails, mark it as unsupported +echo 1 > function_profile_enabled || exit_unsupported + +# Let it run for a bit to make sure nothing explodes +sleep 1 + +exit 0 -- 2.45.2
