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From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug testsuite/30633] [gdb/testsuite, native-gdbserver] FAIL: gdb.dwarf2/typeddwarf.exp: runto: run to main
Date: Wed, 26 Jul 2023 11:42:53 +0000	[thread overview]
Message-ID: <bug-30633-4717-g2gPCFvmby@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-30633-4717@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=30633

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom de Vries <vries@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=bcf43b33cfd3a8415bf272a3ca1af04ec8b9d622

commit bcf43b33cfd3a8415bf272a3ca1af04ec8b9d622
Author: Tom de Vries <tdevries@suse.de>
Date:   Wed Jul 26 13:42:32 2023 +0200

    [gdb/testsuite] Drop -nostdlib in gdb.dwarf2/typeddwarf.exp

    As reported in PR testsuite/30633, when running test-case
    gdb.dwarf2/typeddwarf.exp with target board native-gdbserver on Ubuntu
    22.04.2, we run into:
    ...
    (gdb) continue^M
    Continuing.^M
    ^M
    Program received signal SIGSEGV, Segmentation fault.^M
    0x0000000000000001 in ?? ()^M
    (gdb) FAIL: gdb.dwarf2/typeddwarf.exp: runto: run to main
    ...

    We run into the FAIL as follows:
    - due to using gdbserver, we attach at the point of the first instruction,
in
      _start
    - we then set a breakpoint at main
    - the test-case is a .s file, that has main renamed to _start in the
assembly,
      but not in the debuginfo
    - setting a breakpoint at main sets the breakpoint at the same instruction
      we're currently stopped at
    - continue doesn't hit the breakpoint, and we return out of _start, which
      causes a sigsegv

    Note that this is for the amd64 case (using gdb.dwarf2/typeddwarf-amd64.S).
    For the i386 case (using gdb.dwarf2/typeddwarf.S), setting a breakpoint in
    main sets it one insn after function entry, and consequently the problem
does
    not occur.

    The FAIL is a regression since commit 90cce6c0551 ("[gdb/testsuite] Add
nopie
    in a few test-cases").

    Without nopie the executable is PIE, with nopie it's static instead.

    In the PIE case, we attach at the point of _start in the dynamic linker,
and
    consequently we do not skip the breakpoint in main, and also don't run into
    the FAIL.

    Fix this by:
    - removing the -nostdlib setting, and
    - renaming _start to main in both .S files.

    The change to use -nostdlib and rename main to _start was originally added
    in commit 6edba76fe8b (submitted here:
    https://sourceware.org/pipermail/gdb-patches/2011-May/082657.html ) , I
assume
    to fix the problem now fixed by using nopie.

    Tested on x86_64-linux.

    Reported-By: Simon Marchi <simon.marchi@efficios.com>
    Tested-By: Simon Marchi <simon.marchi@efficios.com>
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30633

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  parent reply	other threads:[~2023-07-26 11:42 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-13 13:19 [Bug testsuite/30633] New: " vries at gcc dot gnu.org
2023-07-13 14:24 ` [Bug testsuite/30633] " vries at gcc dot gnu.org
2023-07-26 11:42 ` cvs-commit at gcc dot gnu.org [this message]
2023-07-26 11:44 ` vries at gcc dot gnu.org

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