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Date: Thu, 20 Jun 2024 20:58:47 +0530
From: Athira Rajeev <atrajeev@...ux.vnet.ibm.com>
To: James Clark <james.clark@....com>, Namhyung Kim <namhyung@...nel.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>
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>, Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Ian Rogers <irogers@...gle.com>
Subject: Re: [PATCH] tools/perf: Handle perftool-testsuite_probe testcases
fail when kernel debuginfo is not present
> On 20 Jun 2024, at 2:03 PM, James Clark <james.clark@....com> wrote:
>
>
>
> On 18/06/2024 11:44, James Clark wrote:
>>
>>
>> On 17/06/2024 17:47, Athira Rajeev wrote:
>>>
>>>
>>>> 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.
>>>
>>
>> Hi Athira,
>>
>> Maybe there is a real bug and this patch is ok to go in and we should leave
>> it as failing. Probe -L shows there is debug info available for inode_permission:
>>
>> $ ./perf probe -L inode_permission
>>
>> <inode_permission@...ux/fs/namei.c:0>
>> 0 int inode_permission(struct mnt_idmap *idmap,
>> struct inode *inode, int mask)
>> ... more source code ...
>>
>> But probe -l has an error which could be related to the following
>> line not showing the filename details:
>>
>> $ ./perf probe -l
>>
>> Failed to find debug information for address 0xffff80008047ac30
>> probe:inode_permission (on inode_permission)
>>
>> I'm running a clang kernel and sometimes I see issues with debug
>> info or toolchain stuff, that could be the reason.
>>
>>> 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.
>>>
>>
>> It passes because there is debug info for getname_flags() which is what the
>> debug info check looks for. After some greps and seds it ultimately does this
>> which succeeds:
>>
>> $ perf probe "vfs_getname=getname_flags:72 pathname=result->name:string"
>>
>> Added new event:
>> probe:vfs_getname (on getname_flags:72 with pathname=result->name:string)
>>
>> "Failed to find debug information for address" is only ever printed
>> with "perf probe -l" when there are probes added. The stderr
>> of that command is never piped into any grep anyway, which is why I
>> see it on the test output.
>>
>> So "probe -L" is working but "probe -l" isn't. Ultimately it looks like a real
>> issue and we should leave the failure in.
>>
>
> To avoid confusion, by leave it in I mean this debuginfo patch is ok and
> the failure I'm seeing is caused by something else.
>
> Reviewed-by: James Clark <james.clark@....com>
Thanks James for the Reviewed-by,
Athira
>
>>> 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'
>>>
>>
>> Here's the full output:
>>
>> $ sudo ./perf test -vvv "testsuite_probe"
>> 84: perftool-testsuite_probe:
>> --- start ---
>> test child forked, pid 4872
>> -- [ 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
>> Failed to find debug information for address 0xffff80008047ac30
>> 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)
>> -- [ 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)
>> Failed to find debug information for address 0xffff80008047ac30
>> -- [ 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
>> -- [ PASS ] -- perf_probe :: test_adding_kernel :: wildcard adding support
>> -- [ PASS ] -- perf_probe :: test_adding_kernel :: non-existing variable
>> -- [ PASS ] -- perf_probe :: test_adding_kernel :: function with retval :: add
>> Regexp not found: "^\[\s+perf\s+record:\s+Woken up [0-9\.]+ times? to write data\s+\].*$"
>> Regexp not found: "^\[\s+perf\s+record:\s+Captured and wrote [0-9\.]+\s*MB\s+(?:[\w\+\.-]*(?:(?:[\w\+\.-]+)?(?:\/[\w\+\.-]+)+)?\/)?perf\.data(?:\.\d+)?\s*\(~?[0-9\.]+ samples\)\s+\].*$"
>> -- [ FAIL ] -- perf_probe :: test_adding_kernel :: function with retval :: record (command exitcode + output regexp parsing)
>> zero-sized data (/tmp/perftool-testsuite_probe.VMU/perf_probe/perf.data), nothing to do!
>> Regexp not found: "\s*cat\s+[0-9\.]+\s+\[[0-9\.]+\]\s+[0-9\.]+:\s+probe:inode_permission\w*:\s+\([0-9A-Fa-f]+\s+<\-\s+[0-9A-Fa-f]+\)\s+arg1=[0-9A-Fa-f]+"
>> -- [ FAIL ] -- perf_probe :: test_adding_kernel :: function argument probing :: script (command exitcode + output regexp parsing)
>> ## [ FAIL ] ## perf_probe :: test_adding_kernel SUMMARY :: 3 failures found
>> ---- end(-1) ----
>> 84: perftool-testsuite_probe : FAILED!
>>
>>
>>>
>>> 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.
>>>
>>
>> $ sudo ./perf probe -L getname_flags
>> Failed to find the path for the kernel: Invalid ELF file
>> Error: Failed to show lines.
>>
>>> 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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