Re: [PATCH v2 2/2] selftests/ftrace: Add new test case which checks for optimized probes

On Tue, 18 Apr 2023 15:25:57 +0530 Akanksha J N akanksha@linux.ibm.com wrote:

Add new test case kprobe_opt_types.tc which enables and checks if each probe has been optimized in order to test potential issues with optimized probes. The '|| continue' is added with the echo statement to ignore errors that are caused by trying to add kprobes to non probeable lines and continue with the test. Signed-off-by: Akanksha J N akanksha@linux.ibm.com

---

.../ftrace/test.d/kprobe/kprobe_opt_types.tc | 34 +++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_opt_types.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_opt_types.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_opt_types.tc new file mode 100644 index 000000000000..54e4800b8a13 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_opt_types.tc @@ -0,0 +1,34 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# Copyright (C) 2023 Akanksha J N, IBM corporation +# description: Register/unregister optimized probe +# requires: kprobe_events

+case `uname -m` in +x86_64) +;; +arm*) +;; +ppc*) +;; +*)

• echo "Please implement other architecture here"
• exit_unsupported

+esac

+DEFAULT=$(cat /proc/sys/debug/kprobes-optimization) +echo 1 > /proc/sys/debug/kprobes-optimization +for i in `seq 0 255`; do

•    echo  "p:testprobe $FUNCTION_FORK+${i}" > kprobe_events || continue
  

•    echo 1 > events/kprobes/enable || continue
  

•    (echo "forked")
  

•    PROBE_TYPE=$(cat /sys/kernel/debug/kprobes/list | grep $FUNCTION_FORK | awk '{print $4}' | awk '{print substr($0,2,length($0)-2)}')
  

I think we can make it simply;

PROBE=$(grep $FUNCTION_FORK /sys/kernel/debug/kprobes/list)

•    echo 0 > events/kprobes/enable
  

•    echo > kprobe_events
  

•    if [ $PROBE_TYPE = "OPTIMIZED" ]; then
  

and

if echo $PROBE | grep -q OPTIMIZED; then

•            echo "$DEFAULT" >  /proc/sys/debug/kprobes-optimization
  

•            exit_pass
  

•    fi
  

+done +echo "$DEFAULT" > /proc/sys/debug/kprobes-optimization +echo "Done"

Hmm, this test does NOT return any error. It always returns success. I understand that optimization may not be possible within 256 bytes from the beginning of the function. In that case, you can return "unresolved", and not echoing "Done" but the reason why it is unresolved.

Thank you,

-- 2.31.1