[perf] perf probe fails sometimes on 4.9

Pintu Kumar pintu.ping at gmail.com
Thu Feb 1 00:20:14 EST 2018


Dear Masami,

Now I am stuck again with 'perf test' failure on 4.9

# perf --version
perf version 4.9.20-<product name>

# perf test
16: Try 'import perf' in python, checking link problems      : FAILED!
37.2: Test BPF prologue generation                           : FAILED!

If you have any clue about these failure please hep me.

Here are the verbose output:
-----------------------------------------------------------------------------
1) # perf test python -v
16: Try 'import perf' in python, checking link problems      :
--- start ---
test child forked, pid 24562
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named perf
test child finished with -1
---- end ----
Try 'import perf' in python, checking link problems: FAILED!
------------------------------------------------------------------------------

2) # perf test BPF -v
-------------------------------------------------------------------------------
.....
bpf: config 'func=null_lseek file->f_mode offset orig' is ok
Looking at the vmlinux_path (8 entries long)
symsrc__init: cannot get elf header.
Failed to find the path for kernel: Invalid ELF file
bpf_probe: failed to convert perf probe eventsFailed to add events
selected by BPF
test child finished with -1
---- end ----
Test BPF filter subtest 1: FAILED!

-------------------------------------------------------------------------------


Thanks,
Pintu


On Wed, Jan 31, 2018 at 9:01 AM, Masami Hiramatsu <mhiramat at kernel.org> wrote:
> On Tue, 30 Jan 2018 19:20:36 +0530
> Pintu Kumar <pintu.ping at gmail.com> wrote:
>
>> On Tue, Jan 30, 2018 at 11:13 AM, Masami Hiramatsu <mhiramat at kernel.org> wrote:
>> >
>> > On Mon, 29 Jan 2018 22:00:52 +0530
>> > Pintu Kumar <pintu.ping at gmail.com> wrote:
>> >
>> > > Dear Masami,
>> > >
>> > > Thank you so much for your reply.
>> > > Please find some of my answers inline.
>> > >
>> > >
>> > > On Mon, Jan 29, 2018 at 7:47 PM, Masami Hiramatsu <mhiramat at kernel.org> wrote:
>> > > > On Mon, 29 Jan 2018 13:40:34 +0530
>> > > > Pintu Kumar <pintu.ping at gmail.com> wrote:
>> > > >
>> > > >> Hi All,
>> > > >>
>> > > >> 'perf probe' is failing sometimes on 4.9.20 with AMD-64.
>> > > >> # perf probe --add schedule
>> > > >> schedule is out of .text, skip it.
>> > > >>   Error: Failed to add events.
>> > > >>
>> > > >> If any one have come across this problem please let me know the cause.
>> > > >
>> > > > Hi Pintu,
>> > > >
>> > > > Could you run it with --vv?
>> > > >
>> > > Ok, I will send verbose output by tomorrow.
>> > >
>> > > >>
>> > > >> Note: I don't have CONFIG_DEBUG_INFO enabled in kernel. Is this the problem?
>> > > >
>> > > > Without it, you can not probe source-level probe nor trace local variable.
>> > > >
>> > >
>> > > Currently I am facing problem in enabling DEBUG_INFO in our kernel 4.9.20
>> > > However, I will try to manually include "-g" option during compilation.
>> > >
>> > > >> However, I manually copied the vmlinux file to /boot/ directory, but
>> > > >> still it does not work.
>> > > >
>> > > > That doesn't work.
>> > > > CONFIG_DEBUG_INFO option enables gcc to compile kernel with extra debuginfo.
>> > > > Without that option, debuginfo is not generated with vmlinux.
>> > > >
>> > > >>
>> > > >> I checked upstream patches until 4.15 but could not find any clue.
>> > > >> Please let me know if there is any fixes available for this.
>> > > >
>> > > > Could you also ensure that you run perf by root user?
>> > > >
>> > >
>> > > Yes I am running with root user.
>> > >
>> > > My concern is sometimes it works but sometimes it fails.
>> >
>> > What I thought was that your kernel enables kptr_strict(but maybe not.)
>> > Can you also try to find "schedule" and "_etext" functions in
>> > /proc/kallsyms?
>> >
>>
>> Yes these functions are present in kallsyms.
>>
>> # cat /proc/kallsyms | grep -w schedule ; cat /proc/kallsyms | grep -w _etext
>> ffffffff829328e0 T schedule
>> ffffffff8293e751 T _etext
>>
>>
>> > > I still needs to figure out, in which condition it works and which
>> > > condition it fails.
>> >
>> > Yeah, it is important.
>> >
>> > > Usually I noticed that in fresh reboot case it works.
>> >
>> > So, after a while, it doesn't work again? If so, it sounds like a daemon
>> > process changes settings in background.
>> >
>>
>> Fortunately or unfortunately, now it is passing every time.
>> Still not sure about the cause.
>> If it fails again, I will collect info with -v and report again.
>> Any specific info that I need to check when it fails ?
>
> OK, if you hit it again, please run perf-probe with -vvv option
> (-v is enough usually, if it is unknown bug, -vvv will be better)
>
> Thank you,
>
>
>>
>> Thank You,
>> Pintu
>>
>>
>> > Thank you,
>> >
>> > >
>> > >
>> > > > Thank you,
>> > > >
>> > > >
>> > > >>
>> > > >>
>> > > >> Thank You!
>> > > >> Regards,
>> > > >> Pintu
>> > > >>
>> > > >>
>> > > >> On Thu, Jan 25, 2018 at 7:09 PM, Pintu Kumar <pintu.ping at gmail.com> wrote:
>> > > >> > Hi,
>> > > >> >
>> > > >> > ** Changed the subject now, since these issues are related to general
>> > > >> > perf commands.
>> > > >> >
>> > > >> > Following are the issues:
>> > > >> >
>> > > >> > 1) perf probe --add schedule - FAILED
>> > > >> > output:
>> > > >> > schedule is out of .text, skip it.
>> > > >> >   Error: Failed to add events.
>> > > >> >
>> > > >> > what is the issue here?
>> > > >> > Sometimes it pass and sometimes it fails...
>> > > >> > Similar is the case of 'perf inject' as well.
>> > > >> >
>> > > >> > 2) perf test - 1 FAILURE
>> > > >> > 37.1: Test basic BPF filtering                               : FAILED!
>> > > >> > 37.2: Test BPF prologue generation                           : Skip
>> > > >> > 37.3: Test BPF relocation checker                            : Skip
>> > > >> >
>> > > >> > bpf: config program 'func=SyS_epoll_wait'
>> > > >> > symbol:SyS_epoll_wait file:(null) line:0 offset:0 return:0 lazy:(null)
>> > > >> > bpf: config 'func=SyS_epoll_wait' is ok
>> > > >> > Looking at the vmlinux_path (8 entries long)
>> > > >> > Using /boot/vmlinux for symbols
>> > > >> > Could not open debuginfo. Try to use symbols.
>> > > >> > SyS_epoll_wait is out of .text, skip it.
>> > > >> > bpf_probe: failed to convert perf probe eventsFailed to add events
>> > > >> > selected by BPF
>> > > >> > test child finished with -1
>> > > >> > ---- end ----
>> > > >> > Test BPF filter subtest 0: FAILED!
>> > > >> >
>> > > >> > Looks like both 1,2 are related.
>> > > >> > Since, CONFIG_DEBUG_INFO is not enabled, I manually copied the vmlinux
>> > > >> > to /boot/ folder.
>> > > >> >
>> > > >> > -------
>> > > >> > Some more info:
>> > > >> >
>> > > >> > Kernel build dir is set to /lib/modules/4.9.20-sc-amd-x86-64/build
>> > > >> > set env: KBUILD_DIR=/lib/modules/4.9.20-sc-amd-x86-64/build
>> > > >> > unset env: KBUILD_OPTS
>> > > >> > include option is set to  -nostdinc -isystem
>> > > >> > /usr/lib/gcc/x86_64-linux-gnu/5/include -I./arch/x86/include
>> > > >> > -I./arch/x86/include/generated/uapi -I./arch/x86/include/generated
>> > > >> > -I./include -I./arch/x86/include/uapi -I./include/uapi
>> > > >> > -I./include/generated/uapi -include ./include/linux/kconfig.h
>> > > >> > set env: NR_CPUS=8
>> > > >> > set env: LINUX_VERSION_CODE=0x40914
>> > > >> > set env: CLANG_EXEC=/usr/bin/clang
>> > > >> > set env: CLANG_OPTIONS=-xc
>> > > >> > set env: KERNEL_INC_OPTIONS= -nostdinc -isystem
>> > > >> > /usr/lib/gcc/x86_64-linux-gnu/5/include -I./arch/x86/include
>> > > >> > -I./arch/x86/include/generated/uapi -I./arch/x86/include/generated
>> > > >> > -I./include -I./arch/x86/include/uapi -I./include/uapi
>> > > >> > -I./include/generated/uapi -include ./include/linux/kconfig.h
>> > > >> > set env: WORKING_DIR=/lib/modules/4.9.20-sc-amd-x86-64/build
>> > > >> >
>> > > >> >
>> > > >> > If you have any clue about these failure please help me.
>> > > >> >
>> > > >> >
>> > > >> > Thanks,
>> > > >> > Pintu
>> > > >> >
>> > > >> >
>> > > >> > On Wed, Jan 24, 2018 at 8:23 PM, Pintu Kumar <pintu.ping at gmail.com> wrote:
>> > > >> >> Hi,
>> > > >> >>
>> > > >> >> Thanks for your help.
>> > > >> >> Yes it was a sub version issue.
>> > > >> >>
>> > > >> >> Earlier, while building the kernel I left the SUBLEVEL as blank.
>> > > >> >>
>> > > >> >> make -j8 bindeb-pkg SUBLEVEL=20
>> > > >> >>
>> > > >> >> After passing the correct sublevel now the test is working.
>> > > >> >>
>> > > >> >> But still following are failing:
>> > > >> >>
>> > > >> >> 16: Try 'import perf' in python, checking link problems      : FAILED!
>> > > >> >> 37.2: Test BPF prologue generation                           : FAILED!
>> > > >> >>
>> > > >> >>
>> > > >> >> This is the error I get:
>> > > >> >>
>> > > >> >> 16: Try 'import perf' in python, checking link problems      :
>> > > >> >> --- start ---
>> > > >> >> test child forked, pid 7637
>> > > >> >> Traceback (most recent call last):
>> > > >> >>   File "<stdin>", line 1, in <module>
>> > > >> >> ImportError: No module named perf
>> > > >> >> test child finished with -1
>> > > >> >> ---- end ----
>> > > >> >> Try 'import perf' in python, checking link problems: FAILED!
>> > > >> >>
>> > > >> >>
>> > > >> >> Looking at the vmlinux_path (8 entries long)
>> > > >> >> symsrc__init: cannot get elf header.
>> > > >> >> Failed to find the path for kernel: Invalid ELF file
>> > > >> >> bpf_probe: failed to convert perf probe eventsFailed to add events
>> > > >> >> selected by BPF
>> > > >> >> test child finished with -1
>> > > >> >> ---- end ----
>> > > >> >> Test BPF filter subtest 1: FAILED!
>> > > >> >>
>> > > >> >>
>> > > >> >>
>> > > >> >> Thanks,
>> > > >> >> Pintu
>> > > >> >>
>> > > >> >>
>> > > >> >> On Wed, Jan 24, 2018 at 6:39 AM, Wangnan (F) <wangnan0 at huawei.com> wrote:
>> > > >> >>>
>> > > >> >>>
>> > > >> >>> On 2018/1/23 20:37, Pintu Kumar wrote:
>> > > >> >>>>
>> > > >> >>>> Hi All,
>> > > >> >>>>
>> > > >> >>>> I am verifying all perf tests on Ubuntu-16 x86-64 platform using the
>> > > >> >>>> kernel version 4.9.20.
>> > > >> >>>> I have installed several others packages including: clang, llvm
>> > > >> >>>>
>> > > >> >>>> But, when I run 'perf test' I get some FAILURE.
>> > > >> >>>> Specially, 'perf test LLVM' is failing.
>> > > >> >>>>
>> > > >> >>>> Please check the below error logs:
>> > > >> >>>>
>> > > >> >>>> ----------------------------------------------------
>> > > >> >>>> # perf test LLVM
>> > > >> >>>> 35: Test LLVM searching and compiling                        :
>> > > >> >>>> 35.1: Basic BPF llvm compiling test                          : FAILED!
>> > > >> >>>> 35.2: Test kbuild searching                                  : Skip
>> > > >> >>>> 35.3: Compile source for BPF prologue generation test        : Skip
>> > > >> >>>> 35.4: Compile source for BPF relocation test                 : Skip
>> > > >> >>>> ----------------------------------------------------
>> > > >> >>>>
>> > > >> >>>> When I run with -v I get this:
>> > > >> >>>>
>> > > >> >>>> -----------------------------------------------------
>> > > >> >>>> # perf test -v LLVM
>> > > >> >>>> 35: Test LLVM searching and compiling                        :
>> > > >> >>>> 35.1: Basic BPF llvm compiling test                          :
>> > > >> >>>> --- start ---
>> > > >> >>>> test child forked, pid 3304
>> > > >> >>>> Unablt to get kernel version from uname '4.9-xxxx-amd-x86-64'
>> > > >> >>>> WARNING:        unable to get correct kernel building directory.
>> > > >> >>>> Hint:   Set correct kbuild directory using 'kbuild-dir' option in [llvm]
>> > > >> >>>>          section of ~/.perfconfig or set it to "" to suppress kbuild
>> > > >> >>>>          detection.
>> > > >> >>>>
>> > > >> >>>> Unablt to get kernel version from uname '4.9-xxxx-amd-x86-64'
>> > > >> >>>>
>> > > >> >>>>
>> > > >> >>>> int _version SEC("version") = LINUX_VERSION_CODE;
>> > > >> >>>> ' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS
>> > > >> >>>> -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS
>> > > >> >>>> $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign
>> > > >> >>>> -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o
>> > > >> >>>> -
>> > > >> >>>> libbpf: 2129190-4a0 doesn't provide kernel version
>> > > >> >>>> Failed to parse test case 'Basic BPF llvm compiling test'
>> > > >> >>>> test child finished with -1
>> > > >> >>>> ---- end ----
>> > > >> >>>> Test LLVM searching and compiling subtest 0: FAILED!
>> > > >> >>>> -----------------------------------------------------
>> > > >> >>>>
>> > > >> >>>>
>> > > >> >>>> Basic BPF LLVM compiling test is failing.
>> > > >> >>>> It reports that bpf could not able to read the kernel version from uname.
>> > > >> >>>> Is it because of this that 'perf test LLVM' is failing ?
>> > > >> >>>>
>> > > >> >>>> My uname says:
>> > > >> >>>> 4.9-xxxx-amd-x86-64
>> > > >> >>>
>> > > >> >>>
>> > > >> >>> 'perf test LLVM' requires a well formed uname string (%d.%d.%d). Please see
>> > > >> >>> tools/perf/fetch_kernel_version . If your distro uses another method to
>> > > >> >>> report
>> > > >> >>> kernel version number (from your uname string, sublevel can't be
>> > > >> >>> determined),
>> > > >> >>> please help us improve that function like what we have done for ubuntu
>> > > >> >>> (checking /proc/version_signature).
>> > > >> >>>
>> > > >> >>>
>> > > >> >>>
>> > > >> >>>> My kernel version is: 4.9.20 (from Makefile)
>> > > >> >>>>
>> > > >> >>>> So, I dont think there is any problem with kernel version.
>> > > >> >>>>
>> > > >> >>>> If any body have come across this problem please let me know how to
>> > > >> >>>> resolve this issue.
>> > > >> >>>>
>> > > >> >>>>
>> > > >> >>>>
>> > > >> >>>> Thank You!
>> > > >> >>>>
>> > > >> >>>> Regards,
>> > > >> >>>> Pintu
>> > > >> >>>
>> > > >> >>>
>> > > >> >>>
>> > > >
>> > > >
>> > > > --
>> > > > Masami Hiramatsu <mhiramat at kernel.org>
>> >
>> >
>> > --
>> > Masami Hiramatsu <mhiramat at kernel.org>
>
>
> --
> Masami Hiramatsu <mhiramat at kernel.org>



More information about the Kernelnewbies mailing list