Bug 19306

Using gdb build from HEAD of today (2019-04-15):
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$ git show -s --pretty="%h %s"
8669f96f0d Automatic date update in version.in
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 https://komiya-dental.com/
Terminal 1:
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$ ./gdb /usr/bin/sleep 
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Terminal 2:
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$ ./gdb -p $(ps -u $USER | grep gdb | awk '{print $1}')
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Terminal 3:
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$ ./gdb -p $(ps -u $USER | grep gdb | awk '{print $1}' | tail -n 1)
(gdb) continue
Continuing. 
... http://www.iu-bloomington.com/

Terminal 2:
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(gdb) set follow-fork-mode child
(gdb) continue
Continuing.
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Terminal 1: https://www.webb-dev.co.uk/ 
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(gdb) run
Starting program: /usr/bin/sleep 
warning: Could not trace the inferior process.
Error: 
warning: ptrace: Action is not allowed
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Terminal 2:
... https://waytowhatsnext.com/  
[Attaching after Thread 0x7fd9945c9ac0 (LWP 15665) vfork to child process 15722]
[New inferior 2 (process 15722)]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
[Detaching vfork parent process 15665 after child exit]
/data/gdb_versions/devel/src/gdb/nat/x86-linux-dregs.c:146: internal-error: void x86_linux_update_debug_registers(lwp_info*): Assertion `lwp_is_stopped (lwp)' failed. http://www.acpirateradio.co.uk/
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
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Terminal 3:
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^C http://www.logoarts.co.uk/ 
Thread 1 "gdb" received signal SIGINT, Interrupt.
0x00007f8c2181807b in poll () from /lib64/libc.so.6
(gdb) bt
#0  0x00007f8c2181807b in poll () from /lib64/libc.so.6 http://www.slipstone.co.uk/ 
#1  0x000000000061bebb in gdb_wait_for_event (block=1) at gdb/event-loop.c:770
#2  0x000000000061b2c2 in gdb_do_one_event () at gdb/event-loop.c:347
#3  0x00000000008caf14 in gdb_readline_wrapper (
    prompt=0x3363230 "gdb/nat/x86-linux-dregs.c:146: internal-error: void x86_linux_update_debug_registers(lwp_info*): Assertion `lwp_is_stopped (lwp)' http://embermanchester.uk/  failed.\nA problem internal to GDB has bee"...) at gdb/top.c:1004
#4  0x00000000009278c1 in defaulted_query(const char *, char, typedef __va_list_tag __va_list_tag *) ( http://connstr.net/ 
    ctlstr=0xc66b68 "%s\nQuit this debugging session? ", defchar=0 '\000', args=0x7ffec3aca140)
    at gdb/utils.c:894 http://joerg.li/ 
#5  0x0000000000927c79 in query (ctlstr=0xc66b68 "%s\nQuit this debugging session? ")
    at gdb/utils.c:986 http://www.jopspeech.com/
#6  0x0000000000926a39 in internal_vproblem(internal_problem *, const char *, int, const char *, typedef __va_list_tag __va_list_tag *) (problem=0x11ac940 <internal_error_problem>,  http://www.wearelondonmade.com/
    file=0xbf4fd8 "gdb/nat/x86-linux-dregs.c", line=146, 
    fmt=0xbf4faa "%s: Assertion `%s' failed.", ap=0x7ffec3aca348) at gdb/utils.c:370
#7  0x0000000000926ccc in internal_verror ( http://www.compilatori.com/
    file=0xbf4fd8 "gdb/nat/x86-linux-dregs.c", line=146, 
    fmt=0xbf4faa "%s: Assertion `%s' failed.", ap=0x7ffec3aca348) at gdb/utils.c:436  http://www-look-4.com/
#8  0x0000000000512f45 in internal_error (

In file included from /usr/include/sched.h:43:0,
                 from ./nat/linux-namespaces.c:30:
/usr/include/bits/sched.h:91:12: note: previous declaration of ‘setns’ was here
 extern int setns (int __fd, int __nstype) __THROW; https://hudsonvalleydeckandfence.com