From 6c78de6eb6f986b2e06e95fabad62731a44aaafd Mon Sep 17 00:00:00 2001 From: Matheus Tavares Bernardino Date: Tue, 1 Aug 2023 12:37:11 -0300 Subject: [PATCH] gdbstub: use 0 ("any process") on packets with no PID Previously, qemu-user would always report PID 1 to GDB. This was changed at dc14a7a6e9 (gdbstub: Report the actual qemu-user pid, 2023-06-30), but read_thread_id() still considers GDB packets with "no PID" as "PID 1", which is not the qemu-user PID. Fix that by parsing "no PID" as "0", which the GDB Remote Protocol defines as "any process". Note that this should have no effect for system emulation as, in this case, gdb_create_default_process() will assign PID 1 for the first process and that is what the gdbstub uses for GDB requests with no PID, or PID 0. This issue was found with hexagon-lldb, which sends a "Hg" packet with only the thread-id, but no process-id, leading to the invalid usage of "PID 1" by qemu-hexagon and a subsequent "E22" reply. Signed-off-by: Matheus Tavares Bernardino Acked-by: Ilya Leoshkevich Message-Id: <78a3b06f6ab90a7ff8e73ae14a996eb27ec76c85.1690904195.git.quic_mathbern@quicinc.com> Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- gdbstub/gdbstub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index ce8b42eb15..e74ecc78cc 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -537,7 +537,7 @@ static GDBThreadIdKind read_thread_id(const char *buf, const char **end_buf, /* Skip '.' */ buf++; } else { - p = 1; + p = 0; } ret = qemu_strtoul(buf, &buf, 16, &t);