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selftests/ftrace: Add a basic testcase for snapshot

This testcase is constrived to reproduce a problem that the cpu buffers
become unavailable which is due to 'record_disabled' of array_buffer and
max_buffer being messed up.

Local test result after bugfix:
  # ./ftracetest test.d/00basic/snapshot1.tc
  === Ftrace unit tests ===
  [1] Snapshot and tracing_cpumask        [PASS]
  [2] (instance)  Snapshot and tracing_cpumask    [PASS]

  # of passed:  2
  # of failed:  0
  # of unresolved:  0
  # of untested:  0
  # of unsupported:  0
  # of xfailed:  0
  # of undefined(test bug):  0

Link: https://lkml.kernel.org/r/20230805033816.3284594-3-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <vnagarnaik@google.com>
Cc: <shuah@kernel.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Zheng Yejian 2023-08-05 11:38:16 +08:00 committed by Steven Rostedt (Google)
parent b71645d6af
commit 5450be6bef

View File

@ -0,0 +1,31 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# description: Snapshot and tracing_cpumask
# requires: trace_marker tracing_cpumask snapshot
# flags: instance
# This testcase is constrived to reproduce a problem that the cpu buffers
# become unavailable which is due to 'record_disabled' of array_buffer and
# max_buffer being messed up.
# Store origin cpumask
ORIG_CPUMASK=`cat tracing_cpumask`
# Stop tracing all cpu
echo 0 > tracing_cpumask
# Take a snapshot of the main buffer
echo 1 > snapshot
# Restore origin cpumask, note that there should be some cpus being traced
echo ${ORIG_CPUMASK} > tracing_cpumask
# Set tracing on
echo 1 > tracing_on
# Write a log into buffer
echo "test input 1" > trace_marker
# Ensure the log writed so that cpu buffers are still available
grep -q "test input 1" trace
exit 0