From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: Pedro Alves <palves@redhat.com>,
Florian Weimer via Libc-alpha <libc-alpha@sourceware.org>,
gdb-patches@sourceware.org
Subject: Re: [PATCH v3] nptl_db: Support different libpthread/ld.so load orders (bug 27744)
Date: Thu, 22 Apr 2021 16:30:10 +0100 [thread overview]
Message-ID: <20210422153008.GM9028@arm.com> (raw)
In-Reply-To: <87pmymgzuy.fsf@oldenburg.str.redhat.com>
The 04/22/2021 16:25, Florian Weimer wrote:
> * 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.)
yes, it seems gdb does not work with
ld.so ./exe
if exe is pie. i could not get it to work wit file either.
add-symbol-file fails even without ld.so, just pie exe fails.
you have to use -o offset argument to add-symbol-file and
manually fish out the base offset from info proc map, i don't
think that can be easily scripted.
next prev parent reply other threads:[~2021-04-22 15:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 10:40 Florian Weimer
2021-04-21 11:47 ` Florian Weimer
2021-04-21 22:35 ` H.J. Lu
2021-04-22 9:29 ` Florian Weimer
2021-04-22 7:28 ` Szabolcs Nagy
2021-04-22 8:33 ` Florian Weimer
2021-04-22 9:05 ` Szabolcs Nagy
2021-04-22 9:48 ` Szabolcs Nagy
2021-04-22 11:55 ` Florian Weimer
2021-04-22 12:44 ` Szabolcs Nagy
2021-04-22 14:20 ` Szabolcs Nagy
2021-04-22 14:25 ` Florian Weimer
2021-04-22 15:30 ` Szabolcs Nagy [this message]
2021-04-22 15:39 ` Florian Weimer
2021-04-22 17:22 ` H.J. Lu
2021-04-22 17:56 ` Florian Weimer
2021-04-22 18:27 ` H.J. Lu
2021-04-22 14:34 ` H.J. Lu
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