[Bug gdb/26861] internal-error: void target_mourn_inferior(ptid_t): Assertion `ptid == inferior_ptid' failed. OS: Mac OSX Catalina; Compiler: GCC; Language: C

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=26861

--- Comment #16 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Simon Marchi <simark@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=dffdd8b51f3fb086faf750592709baa8faa66fd1

commit dffdd8b51f3fb086faf750592709baa8faa66fd1
Author: Simon Marchi <simon.marchi@polymtl.ca>
Date:   Thu Feb 25 15:52:29 2021 -0500

    gdb: relax assertion in target_mourn_inferior

    As reported in PR 26861, when killing an inferior on macOS, we hit the
    assert:

        ../../gdb-10.1/gdb/target.c:2149: internal-error: void
target_mourn_inferior(ptid_t): Assertion `ptid == inferior_ptid' failed.

    This is because darwin_nat_target::kill passes a pid-only ptid to
    target_mourn_inferior, with the pid of the current inferior:

        target_mourn_inferior (ptid_t (inf->pid));

    ... which doesn't satisfy the assert in target_mourn_inferior:

        gdb_assert (ptid == inferior_ptid);

    The reason for this assertion is that target_mourn_inferior is a
    prototype shared between GDB and GDBserver, so that shared code in
    gdb/nat (used in both GDB and GDBserver) can call target_mourn_inferior.
    In GDB's implementation, it is likely that some targets still rely on
    inferior_ptid being set to "the current thread we are working on".  So
    until targets are completely decoupled from inferior_ptid (at least
    their mourn_inferior implementations), we need to ensure the passed in
    ptid matches inferior_ptid, to ensure the calling code called
    target_mourn_inferior with the right global context.

    However, I think the assert is a bit too restrictive.  The
    mourn_inferior operation works on an inferior, not a specific thread.
    And by the time we call mourn_inferior, the threads of the inferior
    don't exist anymore, the process is gone, so it doesn't really make
    sense to require inferior_ptid to point a specific thread.

    I looked at all the target_ops::mourn_inferior implementations, those
    that read inferior_ptid only care about the pid field, which supports
    the idea that only the inferior matters.  Other implementations look at
    the current inferior (call `current_inferior ()`).

    I think it would make sense to change target_mourn_inferior to accept
    only a pid rather than a ptid.  It would then assert that the pid is the
    same as the current inferior's pid.  However, this would be a quite
    involved change, so I'll keep it for later.

    To fix the macOS issue immediately, I propose to relax the assert to
    only compare the pids, as is done in this patch.

    Another solution would obviously be to make darwin_nat_target::kill pass
    inferior_ptid to target_mourn_inferior.  However, the solution I propose
    is more in line with where I think we want to go (passing a pid to
    target_mourn_inferior).

    gdb/ChangeLog:

            PR gdb/26861
            * target.c (target_mourn_inferior): Only compare pids in
            target_mourn_inferior.

    Change-Id: If2439ccc5aa67272ea16148a43c5362ef23fb2b8

-- 
You are receiving this mail because:
You are on the CC list for the bug.