[PATCH v3] nptl_db: Support different libpthread/ld.so load orders (bug 27744)

[Florian Weimer]

* Szabolcs Nagy:

> if i rerun the link command of the test exe but with -no-pie
> instead of -pie then the test passes with that binary.
>
> i suspect gdb places the breakpoint at the wrong place in pie
> for some reason. can be ubuntu tooling specific. see the
> breakpoint location (the exe base offset is missing):

Thanks for investigating.

> +attach 1254516
> [New LWP 1254517]
> Trying host libthread_db library: /home/szabolcs/try/build/nptl_db/libthread_db.so.1.
> td_ta_new failed: application not linked with libthread
> thread_db_load_search returning 0
> Trying host libthread_db library: /home/szabolcs/try/build/nptl_db/libthread_db.so.1.
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/home/szabolcs/try/build/nptl_db/libthread_db.so.1".
> thread_db_load_search returning 1
> 0x0000ffff9d3d89c4 in __futex_abstimed_wait_common64 (futex_word=0xffff9d363210, expected=1254517, clockid=<optimized out>, abstime=0x0, private=<optimized out>, cancel=cancel@entry=true) at futex-internal.c:74
> 74          err = INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word, op, expected,
> +break debugger_inspection_point
> Breakpoint 1 at 0x20c0: file tst-pthread-gdb-attach.c, line 123.
> +continue

Would you please check if the issue goes away if you replace

           "add-symbol-file %1$s/nptl/tst-pthread-gdb-attach\n"

with
           "file %1$s/nptl/tst-pthread-gdb-attach\n"

?

(I assume this happens without --enable-hardcoded-path-in-tests.)

Thanks,
Florian