Re: [GIT PULL] ftrace: Updates for v6.14

[Heiko Carstens]

Hi Steven, Masami,

On Sun, Jan 19, 2025 at 07:31:34PM -0500, Steven Rostedt wrote:
> ftrace updates for v6.14:
> 
> - Have fprobes built on top of function graph infrastructure

this seems to cause a regression:

When I run tools/testing/selftests/ftrace/ftracetest I now end up with all
functions being enabled for ftrace after the test suite ran:

$ wc -l /sys/kernel/debug/tracing/enabled_functions
50779 /sys/kernel/debug/tracing/enabled_functions

$ cat /sys/kernel/debug/tracing/enabled_functions
...
down (1)           
down_interruptible (1)           
down_killable (1)           

$ cat /sys/kernel/debug/tracing/current_tracer
nop

Bisected to commit 4346ba160409 ("fprobe: Rewrite fprobe on function-graph
tracer"). Before this commit there were no ftrace enabled functions after the
test suite finished:

$ wc -l /sys/kernel/debug/tracing/enabled_functions
0 /sys/kernel/debug/tracing/enabled_functions

This is on s390 with defconfig.