[PATCH] tools/perf/tests/base_probe: Fix check for the count of existing probes in test_adding_kernel

[Michael Petlan]

On Mon, 14 Oct 2024, Athira Rajeev wrote:
> perftool-testsuite_probe fails in test_adding_kernel as below:
> 	Regexp not found: "probe:inode_permission_11"
> 	-- [ FAIL ] -- perf_probe :: test_adding_kernel :: force-adding probes ::
> 	second probe adding (with force) (output regexp parsing)
> 	event syntax error: 'probe:inode_permission_11'
> 	  \___ unknown tracepoint
> 
> 	Error:  File /sys/kernel/tracing//events/probe/inode_permission_11
> 	not found.
> 	Hint:   Perhaps this kernel misses some CONFIG_ setting to
> 	enable this feature?.
> 
> The test does the following:
> 1) Adds a probe point first using :
>     $CMD_PERF probe --add $TEST_PROBE
> 2) Then tries to add same probe again without —force
> and expects it to fail. Next tries to add same probe again
> with —force. In this case, perf probe succeeds and adds
> the probe with a suffix number. Example:
> 
>  ./perf probe --add inode_permission
>  Added new event:
>   probe:inode_permission (on inode_permission)
> 
>  ./perf probe --add inode_permission --force
>  Added new event:
>   probe:inode_permission_1 (on inode_permission)
> 
>   ./perf probe --add inode_permission --force
>  Added new event:
>   probe:inode_permission_2 (on inode_permission)
> 
> Each time, suffix is added to existing probe name.
> To get the suffix number, test cases uses :
> NO_OF_PROBES=`$CMD_PERF probe -l | wc -l`
> 
> This will work if there is no other probe existing
> in the system. If there are any other probes other than
> kernel probes or inode_permission, ( example: any probe),
> "perf probe -l" will include count for other probes too.

Hello.

When designing this test, I was relying on the fact that
there are no existing probes, because all should have been
removed at line 43 of the same test:

	40 ### basic probe adding
	41
	42 for opt in "" "-a" "--add"; do
-->	43 	   clear_all_probes
	44 	   $CMD_PERF probe $opt $TEST_PROBE 2> $LOGS_DIR/adding_kernel_add$opt.err
	45 	   PERF_EXIT_CODE=$?
	46
	47	../common/check_all_patterns_found.pl "Added new events?:" "probe:$TEST_PROBE" "on $TEST_PROBE" < $LOGS_DIR/adding_kernel_add$opt.err
	48 	CHECK_EXIT_CODE=$?
	49
	50	print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "adding probe $TEST_PROBE :: $opt"
	51 	(( TEST_RESULT += $? ))
	52 done
	53

I am wondering how it could happen that there were other
probes in the system?

Cheers,

Michael

> 
> Example, in the system where this failed, already some
> probes were default added. So count became 10
>   ./perf probe -l | wc -l
>   10
> 
> So to be specific for "inode_permission", restrict the
> probe count check to that probe point alone using :
> NO_OF_PROBES=`$CMD_PERF probe -l $TEST_PROBE| wc -l`
> 
> Similarly while removing the probe using "probe --del *",
> ( removing all probes ), check uses:
> 
>  ../common/check_all_lines_matched.pl "Removed event: probe:$TEST_PROBE"
> 
> But if there are other probes in the system, the log will
> contain reference to other existing probe too. Hence change
> usage of check_all_lines_matched.pl to check_all_patterns_found.pl
> This will make sure expecting string comes in the result
> 
> Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
> ---
>  tools/perf/tests/shell/base_probe/test_adding_kernel.sh | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/tests/shell/base_probe/test_adding_kernel.sh b/tools/perf/tests/shell/base_probe/test_adding_kernel.sh
> index d541ffd44a93..f8b5f096d0d7 100755
> --- a/tools/perf/tests/shell/base_probe/test_adding_kernel.sh
> +++ b/tools/perf/tests/shell/base_probe/test_adding_kernel.sh
> @@ -169,7 +169,7 @@ print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "force-adding probes :: second pr
>  (( TEST_RESULT += $? ))
>  
>  # adding existing probe with '--force' should pass
> -NO_OF_PROBES=`$CMD_PERF probe -l | wc -l`
> +NO_OF_PROBES=`$CMD_PERF probe -l $TEST_PROBE| wc -l`
>  $CMD_PERF probe --force --add $TEST_PROBE 2> $LOGS_DIR/adding_kernel_forceadd_03.err
>  PERF_EXIT_CODE=$?
>  
> @@ -205,7 +205,7 @@ print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "using doubled probe"
>  $CMD_PERF probe --del \* 2> $LOGS_DIR/adding_kernel_removing_wildcard.err
>  PERF_EXIT_CODE=$?
>  
> -../common/check_all_lines_matched.pl "Removed event: probe:$TEST_PROBE" "Removed event: probe:${TEST_PROBE}_1" < $LOGS_DIR/adding_kernel_removing_wildcard.err
> +../common/check_all_patterns_found.pl "Removed event: probe:$TEST_PROBE" "Removed event: probe:${TEST_PROBE}_1" < $LOGS_DIR/adding_kernel_removing_wildcard.err
>  CHECK_EXIT_CODE=$?
>  
>  print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "removing multiple probes"
> -- 
> 2.43.5
> 
> 
>