bug#34051: 27.0.50; Emacs 27 from master segfaults

[Eli Zaretskii]

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> From: Stefan Husmann <stefan-husmann@t-online.de>
> Date: Sat, 12 Jan 2019 20:48:23 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: stefan-husmann@t-online.de
> >> Date: Sat, 12 Jan 2019 16:46:53 +0100
> >> 
> >> 
> >> Emacs segfaults immediately for me under Arch Linux 64 bit. This happens 
> >> with commit
> >> a1b7a3f2a3957a399d6c3c7bcffa07ac67da82fc and upwards.
> >> 
> >> Commit c342b26371480316024e1e5d63cd8b3f035dda69 works fine.
> >> 
> >> With emacs -Q the segfault does not happen immediately, but it happened
> >> whe I tried to open this bug report.
> >> 
> >> [haawda@frege ~]$ emacs
> >> X protocol error: BadMatch (invalid parameter attributes) on protocol 
> >> request 139
> >> Fatal error 6: Aborted
> >
> > Please run Emacs under a debugger, set x-synchronize to the value of
> > t, then reproduce the problem, and post the backtrace shown by GDB.
> >
> > Thanks.
> 
> Hello,
> 
> this is the output in the affected emacs:
> 
> (gdb) run emacs -Q
> Starting program: /usr/bin/emacs emacs -Q
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/usr/lib/libthread_db.so.1".
> [New Thread 0x7fffeff52700 (LWP 10475)]
> [Detaching after vfork from child process 10614]
> X protocol error: BadMatch (invalid parameter attributes) on protocol request 
> 139
> [Thread 0x7ffff033cdc0 (LWP 10474) exited]
> [Inferior 1 (process 10474) exited with code 0106]
> (gdb) bt full
> No stack.
> (gdb) xbacktrace
> Undefined command: "xbacktrace".  Try "help".
> (gdb)

Thanks, but this not useful because Emacs vforked and GDB stayed with
the wrong process.  Maybe it will be easier for you to convert the
backtrace of addresses you posted with the original report to a
human-readable backtrace; the procedure to do that is described in the
Emacs manual in the node "Crashing".