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Date:   Wed, 31 Jan 2018 12:31:06 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Pintu Kumar <pintu.ping@gmail.com>
Cc:     "Wangnan (F)" <wangnan0@huawei.com>, linux-kernel@vger.kernel.org,
        acme@redhat.com, quentin.monnet@netronome.com,
        daniel@iogearbox.net, davem@davemloft.net,
        alexander.shishkin@linux.intel.com, mingo@redhat.com,
        huawei.libin@huawei.com,
        Alexis Berlemont <alexis.berlemont@gmail.com>,
        maddy@linux.vnet.ibm.com, naveen.n.rao@linux.vnet.ibm.com,
        peterz@infradead.org, kernelnewbies@kernelnewbies.org
Subject: Re: [perf] perf probe fails sometimes on 4.9
Message-Id: <20180131123106.e48e89ab21cceee95f88f405@kernel.org>
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On Tue, 30 Jan 2018 19:20:36 +0530
Pintu Kumar <pintu.ping@gmail.com> wrote:

> On Tue, Jan 30, 2018 at 11:13 AM, Masami Hiramatsu <mhiramat@kernel.org> wrote:
> >
> > On Mon, 29 Jan 2018 22:00:52 +0530
> > Pintu Kumar <pintu.ping@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@kernel.org> wrote:
> > > > On Mon, 29 Jan 2018 13:40:34 +0530
> > > > Pintu Kumar <pintu.ping@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@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@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@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@kernel.org>
> >
> >
> > --
> > Masami Hiramatsu <mhiramat@kernel.org>


-- 
Masami Hiramatsu <mhiramat@kernel.org>