From 758370052fb602f9f23c3b8ae26a6133373c78e6 Mon Sep 17 00:00:00 2001 From: Matheus Tavares Bernardino Date: Thu, 4 May 2023 12:37:31 -0300 Subject: gdbstub: only send stop-reply packets when allowed to MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit GDB's remote serial protocol allows stop-reply messages to be sent by the stub either as a notification packet or as a reply to a GDB command (provided that the cmd accepts such a response). QEMU currently does not implement notification packets, so it should only send stop-replies synchronously and when requested. Nevertheless, it still issues unsolicited stop messages through gdb_vm_state_change(). Although this behavior doesn't seem to cause problems with GDB itself (the messages are just ignored), it can impact other debuggers that implement the GDB remote serial protocol, like hexagon-lldb. Let's change the gdbstub to send stop messages only as a response to a previous GDB command that accepts such a reply. Signed-off-by: Matheus Tavares Bernardino Acked-by: Alex Bennée Signed-off-by: Taylor Simpson Message-Id: --- gdbstub/softmmu.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'gdbstub/softmmu.c') diff --git a/gdbstub/softmmu.c b/gdbstub/softmmu.c index 22ecd09d04..99d994e6bf 100644 --- a/gdbstub/softmmu.c +++ b/gdbstub/softmmu.c @@ -43,6 +43,7 @@ static void reset_gdbserver_state(void) g_free(gdbserver_state.processes); gdbserver_state.processes = NULL; gdbserver_state.process_num = 0; + gdbserver_state.allow_stop_reply = false; } /* @@ -139,6 +140,10 @@ static void gdb_vm_state_change(void *opaque, bool running, RunState state) return; } + if (!gdbserver_state.allow_stop_reply) { + return; + } + gdb_append_thread_id(cpu, tid); switch (state) { @@ -205,6 +210,7 @@ static void gdb_vm_state_change(void *opaque, bool running, RunState state) send_packet: gdb_put_packet(buf->str); + gdbserver_state.allow_stop_reply = false; /* disable single step if it was enabled */ cpu_single_step(cpu, 0); @@ -422,8 +428,11 @@ void gdb_exit(int code) trace_gdbstub_op_exiting((uint8_t)code); - snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code); - gdb_put_packet(buf); + if (gdbserver_state.allow_stop_reply) { + snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code); + gdb_put_packet(buf); + gdbserver_state.allow_stop_reply = false; + } qemu_chr_fe_deinit(&gdbserver_system_state.chr, true); } -- cgit v1.2.3