Date: Mon, 17 Jun 2024 22:17:04 +0530
From: Athira Rajeev <atrajeev@...ux.vnet.ibm.com>
To: James Clark <james.clark@....com>
Cc: LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users <linux-perf-users@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>, akanksha@...ux.ibm.com,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Disha Goel <disgoel@...ux.vnet.ibm.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
        Ian Rogers <irogers@...gle.com>, Namhyung Kim <namhyung@...nel.org>
Subject: Re: [PATCH] tools/perf: Handle perftool-testsuite_probe testcases
 fail when kernel debuginfo is not present



> On 17 Jun 2024, at 8:30 PM, James Clark <james.clark@....com> wrote:
> 
> 
> 
> On 17/06/2024 13:21, Athira Rajeev wrote:
>> Running "perftool-testsuite_probe" fails as below:
>> 
>> ./perf test -v "perftool-testsuite_probe"
>> 83: perftool-testsuite_probe  : FAILED
>> 
>> There are three fails:
>> 
>> 1. Regexp not found: "\s*probe:inode_permission(?:_\d+)?\s+\(on inode_permission(?:[:\+][0-9A-Fa-f]+)?@.+\)"
>>   -- [ FAIL ] -- perf_probe :: test_adding_kernel :: listing added probe :: perf probe -l (output regexp parsing)
>> 
> 
> On a machine where NO_DEBUGINFO gets set, this one skips for me. But on
> a machine where there _is_ debug info this test still fails.
> 
> But in both cases the probe looks like it was added successfully. So I'm
> wondering if this one does need to be skipped, or it's just always
> failing? Do you have this test passing anywhere where there is debug info?
> 
> The list command looks like it successfully lists the probe for me in
> both cases, it just doesn't have an address on the end:
> 
> perf list 'probe:*'
> 
>   probe:inode_permission (on inode_permission)
> 
> Does the missing address mean anything or is it just not handled
> properly by the test?
> 
> Ironically the machine that _does_ pass the debug info test also prints
> this, but it looks like it still adds and lists the probe correctly:
> 
>  perf probe -l probe:*
> 
>  Failed to find debug information for address 0xffff80008047ac30
>    probe:inode_permission (on inode_permission)

Hi James,

Thanks for checking this patch.

In environment where kernel is compiled with debuginfo:

1) Add probe point

# ./perf probe --add inode_permission
Added new event:
  probe:inode_permission (on inode_permission)

You can now use it in all perf tools, such as:

perf record -e probe:inode_permission -aR sleep 1


2) Check using perf probe -l

# ./perf probe -l
probe:inode_permission (on inode_permission:2@...namei.c)

With debuginfo, the result has additional info.
 The test looks for matching pattern "\s*probe:inode_permission(?:_\d+)?\s+\(on inode_permission(?:[:\+][0-9A-Fa-f]+)?@.+\)” in result
where it is expecting "inode_permission:2@...namei.c” . The “@fs/namei.c” info needs debuginfo here.

The function I am using in patch to check for debuginfo (skip_if_no_debuginfo) is from "tests/shell/lib/probe_vfs_getname.sh"

skip_if_no_debuginfo() {
        add_probe_vfs_getname -v 2>&1 | grep -E -q "^(Failed to find the path for the kernel|Debuginfo-analysis is not supported)|(file has no debug information)" && return 2
        return 1
}

So the debuginfo test passes in your case since the log has "Failed to find debug information” which is not present in above grep string. 

James,

Only “perf probe -l” subtest fails with debuginfo enabled or other two subtests as well? Can you also share result on how other two subtests behaves ? 

1. Fail 2 :
   perf probe -nf --max-probes=512 -a 'vfs_* $params’
  

2. Fail 3 :
  perf probe 'vfs_read somenonexistingrandomstuffwhichisalsoprettylongorevenlongertoexceed64'


Also since you mentioned this gets skipped when debuginfo is not enabled, curious to know what is debuginfo message from your setup with debuginfo disabled.

Thanks again for checking.

Athira

> 


> 
>> 2. Regexp not found: "probe:vfs_mknod"
>>   Regexp not found: "probe:vfs_create"
>>   Regexp not found: "probe:vfs_rmdir"
>>   Regexp not found: "probe:vfs_link"
>>   Regexp not found: "probe:vfs_write"
>>   -- [ FAIL ] -- perf_probe :: test_adding_kernel :: wildcard adding support (command exitcode + output regexp parsing)
>> 
>> 3. Regexp not found: "Failed to find"
>>   Regexp not found: "somenonexistingrandomstuffwhichisalsoprettylongorevenlongertoexceed64"
>>   Regexp not found: "in this function|at this address"
>>   Line did not match any pattern: "The /boot/vmlinux file has no debug information."
>>   Line did not match any pattern: "Rebuild with CONFIG_DEBUG_INFO=y, or install an appropriate debuginfo package."
>> 
>> These three tests depends on kernel debug info.
>> 1. Fail 1 expects file name along with probe which needs debuginfo
>> 2. Fail 2 :
>>    perf probe -nf --max-probes=512 -a 'vfs_* $params'
>>    Debuginfo-analysis is not supported.
>>     Error: Failed to add events.
>> 
>> 3. Fail 3 :
>>   perf probe 'vfs_read somenonexistingrandomstuffwhichisalsoprettylongorevenlongertoexceed64'
>>   Debuginfo-analysis is not supported.
>>   Error: Failed to add events.
>> 
>> There is already helper function skip_if_no_debuginfo in
>> lib/probe_vfs_getname.sh which does perf probe and returns
>> "2" if debug info is not present. Use the skip_if_no_debuginfo
>> function and skip only the three tests which needs debuginfo
>> based on the result.
>> 
>> With the patch:
>> 
>>    83: perftool-testsuite_probe:
>>   --- start ---
>>   test child forked, pid 3927
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: adding probe inode_permission ::
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: adding probe inode_permission :: -a
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: adding probe inode_permission :: --add
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: listing added probe :: perf list
>>   Regexp not found: "\s*probe:inode_permission(?:_\d+)?\s+\(on inode_permission(?:[:\+][0-9A-Fa-f]+)?@.+\)"
>>   -- [ SKIP ] -- perf_probe :: test_adding_kernel :: 2 2 Skipped due to missing debuginfo :: testcase skipped
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: using added probe
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: deleting added probe
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: listing removed probe (should NOT be listed)
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: dry run :: adding probe
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: force-adding probes :: first probe adding
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: force-adding probes :: second probe adding (without force)
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: force-adding probes :: second probe adding (with force)
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: using doubled probe
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: removing multiple probes
>>   Regexp not found: "probe:vfs_mknod"
>>   Regexp not found: "probe:vfs_create"
>>   Regexp not found: "probe:vfs_rmdir"
>>   Regexp not found: "probe:vfs_link"
>>   Regexp not found: "probe:vfs_write"
>>   -- [ SKIP ] -- perf_probe :: test_adding_kernel :: 2 2 Skipped due to missing debuginfo :: testcase skipped
>>   Regexp not found: "Failed to find"
>>   Regexp not found: "somenonexistingrandomstuffwhichisalsoprettylongorevenlongertoexceed64"
>>   Regexp not found: "in this function|at this address"
>>   Line did not match any pattern: "The /boot/vmlinux file has no debug information."
>>   Line did not match any pattern: "Rebuild with CONFIG_DEBUG_INFO=y, or install an appropriate debuginfo package."
>>   -- [ SKIP ] -- perf_probe :: test_adding_kernel :: 2 2 Skipped due to missing debuginfo :: testcase skipped
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: function with retval :: add
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: function with retval :: record
>>   -- [ PASS ] -- perf_probe :: test_adding_kernel :: function argument probing :: script
>>   ## [ PASS ] ## perf_probe :: test_adding_kernel SUMMARY
>>   ---- end(0) ----
>>   83: perftool-testsuite_probe                                        : Ok
>> 
>> Only the three specific tests are skipped and remaining
>> ran successfully.
>> 
>> Signed-off-by: Athira Rajeev <atrajeev@...ux.vnet.ibm.com>
>> ---
>> .../shell/base_probe/test_adding_kernel.sh    | 31 +++++++++++++++++--
>> 1 file changed, 28 insertions(+), 3 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 63bb8974b38e..187dc8d4b163 100755
>> --- a/tools/perf/tests/shell/base_probe/test_adding_kernel.sh
>> +++ b/tools/perf/tests/shell/base_probe/test_adding_kernel.sh
>> @@ -21,8 +21,18 @@
>> THIS_TEST_NAME=`basename $0 .sh`
>> TEST_RESULT=0
>> 
>> +# shellcheck source=lib/probe_vfs_getname.sh
>> +. "$(dirname "$0")/../lib/probe_vfs_getname.sh"
>> +
>> TEST_PROBE=${TEST_PROBE:-"inode_permission"}
>> 
>> +# set NO_DEBUGINFO to skip testcase if debuginfo is not present
>> +# skip_if_no_debuginfo returns 2 if debuginfo is not present
>> +skip_if_no_debuginfo
>> +if [ $? -eq 2 ]; then
>> + NO_DEBUGINFO=1
>> +fi
>> +
>> check_kprobes_available
>> if [ $? -ne 0 ]; then
>> print_overall_skipped
>> @@ -67,7 +77,12 @@ PERF_EXIT_CODE=$?
>> ../common/check_all_patterns_found.pl "\s*probe:${TEST_PROBE}(?:_\d+)?\s+\(on ${TEST_PROBE}(?:[:\+]$RE_NUMBER_HEX)?@.+\)" < $LOGS_DIR/adding_kernel_list-l.log
>> CHECK_EXIT_CODE=$?
>> 
>> -print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "listing added probe :: perf probe -l"
>> +if [ $NO_DEBUGINFO ] ; then
>> + print_testcase_skipped $NO_DEBUGINFO $NO_DEBUGINFO "Skipped due to missing debuginfo"
>> +else
>> + print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "listing added probe :: perf probe -l"
>> +fi
>> +
>> (( TEST_RESULT += $? ))
>> 
>> 
>> @@ -208,7 +223,12 @@ PERF_EXIT_CODE=$?
>> ../common/check_all_patterns_found.pl "probe:vfs_mknod" "probe:vfs_create" "probe:vfs_rmdir" "probe:vfs_link" "probe:vfs_write" < $LOGS_DIR/adding_kernel_adding_wildcard.err
>> CHECK_EXIT_CODE=$?
>> 
>> -print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "wildcard adding support"
>> +if [ $NO_DEBUGINFO ] ; then
>> + print_testcase_skipped $NO_DEBUGINFO $NO_DEBUGINFO "Skipped due to missing debuginfo"
>> +else
>> + print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "wildcard adding support"
>> +fi
>> +
>> (( TEST_RESULT += $? ))
>> 
>> 
>> @@ -232,7 +252,12 @@ CHECK_EXIT_CODE=$?
>> ../common/check_no_patterns_found.pl "$RE_SEGFAULT" < $LOGS_DIR/adding_kernel_nonexisting.err
>> (( CHECK_EXIT_CODE += $? ))
>> 
>> -print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "non-existing variable"
>> +if [ $NO_DEBUGINFO ]; then
>> + print_testcase_skipped $NO_DEBUGINFO $NO_DEBUGINFO "Skipped due to missing debuginfo"
>> +else
>> + print_results $PERF_EXIT_CODE $CHECK_EXIT_CODE "non-existing variable"
>> +fi
>> +
>> (( TEST_RESULT += $? ))
>> 
>> 

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