On Wed, 21 Aug 2024 21:54:42 -0600 Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote: > On 8/21/24 13:09, Steven Rostedt wrote: > > 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 > > > > Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> > > --- > > .../ftrace/test.d/ftrace/fgraph-profiler.tc | 30 +++++++++++++++++++ > > 1 file changed, 30 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..62d44a1395da > > --- /dev/null > > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-profiler.tc > > @@ -0,0 +1,30 @@ > > +#!/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 function_graph and profiling to 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 > > + > > +sleep 1 > > Any specific reason for this sleep 1 - can you add a comment on top? We add sleep 1 in several locations of the ftrace selftests to let the tracing run for a bit just to see if it triggers anything. Otherwise the clean up can happen before anything gets traced. Although, it's highly unlikely in this case, but still. I could add a comment if you want of just: # let it run for a bit sleep 1 > > + > > +exit 0 > > Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> > > Let me know if you would like v2 for this to be taken through my tree. I'll make a v2 if you want me to. -- Steve
