buildbot failure in LLVM on clang-x86_64-ubuntu-gdb-75

This bot seems kind of flaky. In the last 100 builds, it has failed
"gdb-75-check" 22 times with what is either a linker error or a missing
header (or both?):

    gdb compile failed, /usr/bin/ld: error: /home/buildslave/osuosl_slave/clang-x86_64-ubuntu-gdb-75/clang-tests/build/gdb/testsuite/gdb.trace/pendshr1.c.o: requires dynamic R_X86_64_PC32 reloc against 'pendfunc1' which may overflow at runtime; recompile with -fPIC
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    Running ../../../src/gdb/testsuite/gdb.trace/report.exp ...
    Running ../../../src/gdb/testsuite/gdb.trace/save-trace.exp ...
    Running ../../../src/gdb/testsuite/gdb.trace/stap-trace.exp ...
    gdb compile failed, ../../../src/gdb/testsuite/gdb.trace/stap-trace.c:34:10: fatal error: 'sys/sdt.h' file not found
    #include <sys/sdt.h>
             ^
    1 error generated.

Could whoever administers this bot please look into this and either fix
or disable the flaky test?

llvm.buildmaster@lab.llvm.org writes:

David, is this yours?

Yep, this is mine - I’ve noticed the flakyness, but have little/no idea what introduced it (it’s possible the machine updated and produced some oddity)

Open to any guesses, but yeah - it’s on me to get that sorted out. Possibly in the interim (or permanently) that test case just be disabled… (I think it’s consistently the same test)

Adrian was nice enough to check on the machine & clean out some stuck processes.

It seems to be a bit greener now… fingers crossed