On Wed, 03 Jul 2019 15:50:00 -0400 Steven Rostedt <rost...@goodmis.org> wrote:
> From: "Steven Rostedt (VMware)" <rost...@goodmis.org> > > If the kernel is not configured with ftrace enabled, the ftracetest > selftests should return the error code of "4" as that is the kselftests > "skip" code, and not "1" which means an error. > > To determine if ftrace is enabled, first the newer "tracefs" is searched for > in /proc/mounts. If it is not found, then "debugfs" is searched for (as old > kernels do not have tracefs). If that is not found, an attempt to mount the > tracefs or debugfs is performed. This is done by seeing first if the > /sys/kernel/tracing directory exists. If it does than tracefs is configured > in the kernel and an attempt to mount it is performed. > > If /sys/kernel/tracing does not exist, then /sys/kernel/debug is tested to > see if that directory exists. If it does, then an attempt to mount debugfs > on that directory is performed. If it does not exist, then debugfs is not > configured in the running kernel and the test exits with the skip code. > > If either mount fails, then a normal error is returned as they do exist in > the kernel but something went wrong to mount them. > > This changes the test to always try the tracefs file system first as it has > been in the kernel for some time now and it is better to test it if it is > available instead of always testing debugfs. > > Link: http://lkml.kernel.org/r/20190702062358.7330-1-po-hsu....@canonical.com > > Reported-by: Po-Hsu Lin <po-hsu....@canonical.com> > Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> > --- > tools/testing/selftests/ftrace/ftracetest | 38 +++++++++++++++++++---- > 1 file changed, 32 insertions(+), 6 deletions(-) > > diff --git a/tools/testing/selftests/ftrace/ftracetest > b/tools/testing/selftests/ftrace/ftracetest > index 136387422b00..edf5ea35d2a7 100755 > --- a/tools/testing/selftests/ftrace/ftracetest > +++ b/tools/testing/selftests/ftrace/ftracetest > @@ -23,9 +23,15 @@ echo " If <dir> is -, all logs > output in console only" > exit $1 > } > > +# default error > +err_ret=1 > + > +# kselftest skip code is 4 > +err_skip=4 > + > errexit() { # message > echo "Error: $1" 1>&2 > - exit 1 > + exit $err_ret > } > > # Ensuring user privilege > @@ -116,11 +122,31 @@ parse_opts() { # opts > } > > # Parameters > -DEBUGFS_DIR=`grep debugfs /proc/mounts | cut -f2 -d' ' | head -1` > -if [ -z "$DEBUGFS_DIR" ]; then > - TRACING_DIR=`grep tracefs /proc/mounts | cut -f2 -d' ' | head -1` > -else > - TRACING_DIR=$DEBUGFS_DIR/tracing > +TRACING_DIR=`grep tracefs /proc/mounts | cut -f2 -d' ' | head -1` > +if [ -z "$TRACING_DIR" ]; then > + DEBUGFS_DIR=`grep debugfs /proc/mounts | cut -f2 -d' ' | head -1` > + if [ -z "$DEBUGFS_DIR" ]; then > + # If tracefs exists, then so does /sys/kernel/tracing Ah, indeed. the mount point also may not exist on older kernel. OK, this looks good to me. Acked-by: Masami Hiramatsu <mhira...@kernel.org> Thank you! > + if [ -d "/sys/kernel/tracing" ]; then > + mount -t tracefs nodev /sys/kernel/tracing || > + errexit "Failed to mount /sys/kernel/tracing" > + TRACING_DIR="/sys/kernel/tracing" > + # If debugfs exists, then so does /sys/kernel/debug > + elif [ -d "/sys/kernel/debug" ]; then > + mount -t debugfs nodev /sys/kernel/debug || > + errexit "Failed to mount /sys/kernel/debug" > + TRACING_DIR="/sys/kernel/debug/tracing" > + else > + err_ret=$err_skip > + errexit "debugfs and tracefs are not configured in this kernel" > + fi > + else > + TRACING_DIR="$DEBUGFS_DIR/tracing" > + fi > +fi > +if [ ! -d "$TRACING_DIR" ]; then > + err_ret=$err_skip > + errexit "ftrace is not configured in this kernel" > fi > > TOP_DIR=`absdir $0` > -- > 2.20.1 > > -- Masami Hiramatsu <mhira...@kernel.org>
