Assertion failed when interrupting/continuing multiple threads

[simark]

While itfocusing two threads, interrupt, continue and interrupt again.

(gdb) status
    Id   Target Id         Status 
  1 (process 17081) [/home/emaisin/build/binutils-gdb-itsets/gdb/threads]
    1.1  Thread 0x7ffff7fc5740 (LWP 17081) "threads" all_threads_started () at threads.c:32
    1.2  Thread 0x7ffff77f6700 (LWP 17085) "threads" (running)
    1.3  Thread 0x7ffff6ff5700 (LWP 17086) "threads" (running)
    1.4  Thread 0x7ffff67f4700 (LWP 17087) "threads" (running)
    1.5  Thread 0x7ffff5ff3700 (LWP 17088) "threads" (running)
  2 (process 17089) [/home/emaisin/build/binutils-gdb-itsets/gdb/threads]
*   2.1  Thread 0x7ffff7fc5740 (LWP 17089) "threads" all_threads_started () at threads.c:32
    2.2  Thread 0x7ffff77f6700 (LWP 17090) "threads" (running)
    2.3  Thread 0x7ffff6ff5700 (LWP 17091) "threads" (running)
    2.4  Thread 0x7ffff67f4700 (LWP 17092) "threads" (running)
    2.5  Thread 0x7ffff5ff3700 (LWP 17093) "threads" (running)
(gdb) itfocus tt1.2,tt2.2
Focus is `tt1.2,tt2.2'.
Current inferior is 1.
Current thread is 2.
(gdb) interrupt 
(gdb) 
[Thread 0x7ffff77f6700 (LWP 17085)] #2 stopped.
0x00007ffff78b7dfd in nanosleep () from /lib/x86_64-linux-gnu/libc.so.6

[Thread 0x7ffff77f6700 (LWP 17090)] #7 stopped.
0x00007ffff78b7dfd in nanosleep () from /lib/x86_64-linux-gnu/libc.so.6

(gdb) status
    Id   Target Id         Status 
  1 (process 17081) [/home/emaisin/build/binutils-gdb-itsets/gdb/threads]
*   1.2  Thread 0x7ffff77f6700 (LWP 17085) "threads" 0x00007ffff78b7dfd in nanosleep ()
   from /lib/x86_64-linux-gnu/libc.so.6
  2 (process 17089) [/home/emaisin/build/binutils-gdb-itsets/gdb/threads]
+   2.2  Thread 0x7ffff77f6700 (LWP 17090) "threads" 0x00007ffff78b7dfd in nanosleep ()
   from /lib/x86_64-linux-gnu/libc.so.6
(gdb) c &
Continuing.
(gdb) status
    Id   Target Id         Status 
  1 (process 17081) [/home/emaisin/build/binutils-gdb-itsets/gdb/threads]
*   1.2  Thread 0x7ffff77f6700 (LWP 17085) "threads" (running)
  2 (process 17089) [/home/emaisin/build/binutils-gdb-itsets/gdb/threads]
+   2.2  Thread 0x7ffff77f6700 (LWP 17090) "threads" (running)
(gdb) interrupt 
/home/emaisin/src/binutils-gdb/gdb/inline-frame.c:338: internal-error: skip_inline_frames: Assertion `find_inline_frame_state (ptid) == NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) y