Problem description: gdbserver is not possible to attach to a multithreaded application when non-stop and target-async options are enabled. Scenario: # gdbserver :23946 --attach 1374 & [1] 8154 # Attached; pid = 1374 Listening on port 23946 # gdb GNU gdb (Wind River Linux Sourcery CodeBench 4.8-40) 7.6 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "powerpc64-wrs-linux-gnu". For bug reporting instructions, please see: <support@windriver.com>. (gdb) set non-stop on (gdb) set target-async (gdb) target remote :23946 Remote debugging from host 127.0.0.1 Remote debugging using :23946 [New Thread 1374] [New Thread 1378] [New Thread 1379] [New Thread 1394] ... [New Thread 1581] /wrs-4.8/40/src/gdb-7.6-yocto/gdb/gdbserver/server.c:2469: A problem internal to GDBserver has been detected. queue_stop_reply_callback: Assertion `thread->last_status.kind != TARGET_WAITKIND_IGNORE' failed. Remote connection closed This can also be reproduced on x86 machines. The problem looks similar to the one reported upstream in https://sourceware.org/bugzilla/show_bug.cgi?id=16769 Reproduced on: WR Linux 600.16. BSP: EPB2 (based on fsl-t4xxx)