Re: How to track the functions in self-written module using SystemTap?

[Nan Xiao <xiaonan830818@gmail.com>]

> Hmm. OK, let's try a couple more things:

> 1) It could be that systemtap is missing the module load somehow. So,
> try this:

> - load the module
> - run stap
> - exercise the module
> - unload the module
> - kill stap

Still outputs nothing.

> 2) It looks like you are running the rpm version. Can you install the
> systemtap-testsuite rpm and try the following (as root):

> # cd /usr/share/systemtap/testsuite
> # make installcheck RUNTESTFLAGS="modules_out_of_tree.exp kmodule.exp"

> That should run 2 testcases that test out-of-tree modules and in-tree
> modules.

The output likes this:

# make installcheck RUNTESTFLAGS="modules_out_of_tree.exp kmodule.exp"
Making a new site.exp file ...
rmmod uprobes 2>/dev/null
make: [installcheck] Error 1 (ignored)
make  check-DEJAGNU RUNTESTFLAGS="modules_out_of_tree.exp kmodule.exp
--tool_opts \'install \'"
make[1]: Entering directory `/usr/share/systemtap/testsuite'
srcdir='.'; export srcdir; \
EXPECT=expect; export EXPECT; \
if /bin/sh -c "env XDG_DATA_DIRS= SYSTEMTAP_SYNC=1 LANG=C
SYSTEMTAP_TESTREMOTES= SYSTEMTAP_TESTAPPS=
SYSTEMTAP_RUNTIME=/usr/share/systemtap/runtime
SYSTEMTAP_TAPSET=/usr/share/systemtap/tapset
LD_LIBRARY_PATH=/usr/lib64/systemtap CRASH_LIBDIR=/usr/lib64/systemtap
PATH=/usr/bin:$PATH SYSTEMTAP_PATH=/usr/bin
SYSTEMTAP_INCLUDES=/usr/include  PKGLIBDIR=/usr/libexec/systemtap
./execrc runtest --version" > /dev/null 2>&1; then \
  exit_status=0; l='systemtap'; for tool in $l; do \
    if env XDG_DATA_DIRS= SYSTEMTAP_SYNC=1 LANG=C
SYSTEMTAP_TESTREMOTES= SYSTEMTAP_TESTAPPS=
SYSTEMTAP_RUNTIME=/usr/share/systemtap/runtime
SYSTEMTAP_TAPSET=/usr/share/systemtap/tapset
LD_LIBRARY_PATH=/usr/lib64/systemtap CRASH_LIBDIR=/usr/lib64/systemtap
PATH=/usr/bin:$PATH SYSTEMTAP_PATH=/usr/bin
SYSTEMTAP_INCLUDES=/usr/include  PKGLIBDIR=/usr/libexec/systemtap
./execrc runtest  --tool $tool --tool_opts \'\' --srcdir $srcdir
modules_out_of_tree.exp kmodule.exp --tool_opts \'install \'; \
    then :; else exit_status=1; fi; \
  done; \
else echo "WARNING: could not find 'env XDG_DATA_DIRS=
SYSTEMTAP_SYNC=1 LANG=C SYSTEMTAP_TESTREMOTES= SYSTEMTAP_TESTAPPS=
SYSTEMTAP_RUNTIME=/usr/share/systemtap/runtime
SYSTEMTAP_TAPSET=/usr/share/systemtap/tapset
LD_LIBRARY_PATH=/usr/lib64/systemtap CRASH_LIBDIR=/usr/lib64/systemtap
PATH=/usr/bin:$PATH SYSTEMTAP_PATH=/usr/bin
SYSTEMTAP_INCLUDES=/usr/include  PKGLIBDIR=/usr/libexec/systemtap
./execrc runtest'" 1>&2; :;\
fi; \
exit $exit_status
WARNING: Couldn't find the global config file.
kernel location: /usr/lib/debug/lib/modules/3.10.0-123.el7.x86_64.debug/vmlinux
kernel version: 3.10.0-123.el7.x86_64.debug
systemtap location: /usr/bin/stap
systemtap version: version 2.4/0.158, rpm 2.4-14.el7
gcc location: /usr/bin/gcc
gcc version: gcc (GCC) 4.8.2 20140120 (Red Hat 4.8.2-16)
spawn -ignore SIGHUP gcc hello.c -g -m64 -lm -o hello-m64
spawn -ignore SIGHUP gcc hello.c -g -m32 -lm -o hello-m32
/usr/bin/ld: skipping incompatible
/usr/lib/gcc/x86_64-redhat-linux/4.8.2/libgcc_s.so when searching for
-lgcc_s
/usr/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status



**** failed gcc m32 smoke test:

/usr/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status

Please install libgcc and glibc development packages for m32


**** aborting testing.

make[1]: Leaving directory `/usr/share/systemtap/testsuite'
if test -n ""; then mail  < systemtap.sum; fi


Thanks!
Best Regards
Nan Xiao


On Wed, Dec 2, 2015 at 12:27 AM, David Smith <dsmith@redhat.com> wrote:
> On 11/30/2015 08:57 PM, Nan Xiao wrote:
>> Hi Frank,
>>
>> I have just tested it:
>>
>> # dd if=kex of=/dev/null bs=101 count=1
>> 0+1 records in
>> 0+1 records out
>> 100 bytes (100 B) copied, 0.00278675 s, 35.9 kB/s
>>
>> But still nothing outputs:
>> # stap -v -e 'probe
>> module("/root/kernel/105.ops/kex.ko").function("*") { printf("%s\n",
>> ppfunc()) }'
>> Pass 1: parsed user script and 100 library script(s) using
>> 210544virt/28008res/3036shr/25484data kb, in 110usr/50sys/162real ms.
>> Pass 2: analyzed script: 6 probe(s), 1 function(s), 0 embed(s), 0
>> global(s) using 370776virt/29748res/3596shr/26612data kb, in
>> 30usr/760sys/802real ms.
>> Pass 3: using cached
>> /root/.systemtap/cache/5c/stap_5cfec0f637bce0fa61c51d4186192dd5_2853.c
>> Pass 4: using cached
>> /root/.systemtap/cache/5c/stap_5cfec0f637bce0fa61c51d4186192dd5_2853.ko
>> Pass 5: starting run.
>>
>> Thanks!
>> Best Regards
>> Nan Xiao
>>
>>
>> On Tue, Dec 1, 2015 at 10:18 AM, Frank Ch. Eigler <fche@redhat.com> wrote:
>>> Nan Xiao <xiaonan830818@gmail.com> writes:
>>>
>>>> [...]
>>>> run "# stap -e 'probe
>>>> module("/root/kernel/105.ops/kex.ko").function("*") { printf("%s\n",
>>>> ppfunc()) }'", but
>>>> run "insmod kex.ko" & "rmmod kex" still outputs nothing.
>>>
>>> Xan you exercise kex.ko beyond just installing & removing it right
>>> away, while the systemtap script is probing it?
>>>
>>> - FChE
>
> Hmm. OK, let's try a couple more things:
>
> 1) It could be that systemtap is missing the module load somehow. So,
> try this:
>
> - load the module
> - run stap
> - exercise the module
> - unload the module
> - kill stap
>
> 2) It looks like you are running the rpm version. Can you install the
> systemtap-testsuite rpm and try the following (as root):
>
> # cd /usr/share/systemtap/testsuite
> # make installcheck RUNTESTFLAGS="modules_out_of_tree.exp kmodule.exp"
>
> That should run 2 testcases that test out-of-tree modules and in-tree
> modules.
>
> --
> David Smith
> dsmith@redhat.com
> Red Hat
> http://www.redhat.com
> 256.217.0141 (direct)
> 256.837.0057 (fax)