A gdbserver does not report a ptid in a 'W' or 'X' packet if multi-process
extensions are not supported or turned off. See
https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html#multiprocess-extensionshttps://sourceware.org/gdb/current/onlinedocs/gdb/Stop-Reply-Packets.html#Stop-Reply-Packets
GDB's remote packet parser checks for whether a stop-reply packet
contains a ptid if the target is non-stop, and issues an error if no
ptid is included:
if (target_is_non_stop_p () && event->ptid == null_ptid)
error (_("No process or thread specified in stop reply: %s"), buf);
This leads to the following error when the non-stop
mode is turned on but multi-process extensions are off:
$ gdb
(gdb) set non-stop on
(gdb) set remote multiprocess-feature-packet off
(gdb) target remote | gdbserver - ./foo
Remote debugging using | gdbserver - ./foo
stdin/stdout redirected
Process ./foo created; pid = 3712
...
(gdb) continue
Continuing.
...
No process or thread specified in stop reply: W2a
(gdb)
Because the check is done for stop reply packets in general, a similar
situation occurs if the 'T' or 'Tthread' packet is disabled in
gdbserver (i.e. via --disable-packet=T). E.g:
$ gdb
(gdb) set non-stop on
(gdb) target remote | gdbserver --disable-packet=Tthread - ./foo
...
No process or thread specified in stop reply: T0506:0000000000000000;07:10e2ffffff7f0000;10:9060ddf7ff7f0000;
or
$ gdb
(gdb) set non-stop on
(gdb) target remote | gdbserver --disable-packet=T - ./foo
...
No process or thread specified in stop reply: S05
The commit
commit cada5fc921
Date: Wed Mar 11 12:30:13 2020 +0000
gdb: Handle W and X remote packets without giving a warning
and its predecessor
commit 24ed6739b6
Date: Thu Jan 30 14:35:40 2020 +0000
gdb/remote: Restore support for 'S' stop reply packet
added warnings for when GDB has to make a guess for a missing ptid in
case of multiple threads/inferiors. These warnings should suffice.
So, the simple solution is to remove the check completely.
Regression-tested on X86_64 Linux.
gdb/ChangeLog:
2020-04-01 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* remote.c (remote_target::remote_parse_stop_reply): Remove the
check for no ptid in the stop reply when the target is non-stop.
gdb/testsuite/ChangeLog:
2020-04-01 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.server/stop-reply-no-thread.exp: Enhance the test
scenario to cover execution until the end and also the case
when no packet is disabled when starting gdbserver.
e139a727be