Dynamorio failing with dmesg error "vsyscall read attempt denied"

[Jay Shah]

Hello:

I am trying to compile and run dynamorio drcachesim on x86 linux. I was able to succesfully compile it and when I test try the command below - it looks like it goes through but when I read the dmesg buffer - this is what is printed out:

root@iclgpa:/home/lab/jashah/dynamorio/build# dmesg
root@iclgpa:/home/lab/jashah/dynamorio/build# bin64/drrun echo "hello world"
hello world
root@iclgpa:/home/lab/jashah/dynamorio/build# dmesg
[1734480.827598] echo[510897] vsyscall read attempt denied -- look up the vsyscall kernel parameter if you need a workaround ip:7fa19a3e1dc3 cs:33 sp:7ffd776fb948 ax:ffffffffff600000 si:ffffffffff600000 di:7ffd776fb970
root@iclgpa:/home/lab/jashah/dynamorio/build#

Has anyone seen this error before and does anyone know how to fix this?

Thaks,

Jay

[Derek Bruening]

I believe that is just a warning and nothing actually failed: I assume the exit code is 0 and everything worked just fine.  Xref https://github.com/DynamoRIO/dynamorio/issues/5570#issuecomment-1190699147.  If you'd like to help eliminate the attempt to read vsyscall as a cleanup that would be great: maybe start by filing an issue and then submit a pull request.

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[Jay Shah]

Hi Derek:

I'm not very sure why it doesn't seem to work because I have another ARM system and the build works just fine on there.

This is from my ARM system output:
$ bin64/drrun -t drcachesim -- ls
api      cmake             CMakeDoxygenDefaults.cmake  configure_defines.h  core                     decode_gen.h        drcpusim.drrun64  ext      libutil   opcode_api.h
bin64    CMakeCache.txt    CMakeFiles                  configure.h          CPackConfig.cmake        drcachesim.drrun64  encode_gen.h      include  logs      opcode_names.h
clients  CMakeDoxyfile.in  cmake_install.cmake         configure_temp.h     CPackSourceConfig.cmake  drcov.drrun64       event_strings.h   lib64    Makefile  tools
---- <application exited with code 0> ----
Cache simulation results:
Core #0 (1 thread(s))
  L1I stats:
    Hits:                          528,602
    Misses:                          1,788
    Invalidations:                       0
    Miss rate:                        0.34%
  L1D stats:
    Hits:                          157,389
    Misses:                          4,123
    Invalidations:                       0
    Prefetch hits:                     981
    Prefetch misses:                 3,425
    Miss rate:                        2.55%
Core #1 (0 thread(s))
Core #2 (0 thread(s))
Core #3 (0 thread(s))
LL stats:
    Hits:                            1,887
    Misses:                          4,024
    Invalidations:                       0
    Prefetch hits:                   1,174
    Prefetch misses:                 2,251
    Local miss rate:                 68.08%
    Child hits:                    686,972
    Total miss rate:                  0.58%

But when I run the same command on my x86 system, my executable just hangs.

I tried running drrun.debug and this is the error I get:
$ bin64/drrun.debug -t drcachesim -- ls
-bash: bin64/drrun.debug: cannot execute binary file: Exec format error

Do you know what this error is? I tried searching for what the error may be but nothing helpful seems to come up.

Both the version of dynamorio were installed by following instructions on the page here: https://dynamorio.org/page_building.html

Any help would be really appreciated. :)

Thanks,

Jay

[Derek Bruening]

Does plain drrun without any tool work?

Do other tools than online drcachesim work?

Online drcachesim makes a pipe and waits on it and errors in the pipe can cause hangs: is it waiting on a stale pipe?

Running or attaching in the debugger to see where it is would generally be the first step to diagnose a hang.

 

I tried running drrun.debug and this is the error I get:

$ bin64/drrun.debug -t drcachesim -- ls
-bash: bin64/drrun.debug: cannot execute binary file: Exec format error

A .debug file is not for execution: it contains debug info.  As the documentation https://dynamorio.org/page_debugging.html says pass "-debug" to drrun to use the debug build.

 

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