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X-Received-From: 2607:f8b0:4864:20::1042 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, Changbin Du Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @gmail.com) Recently when debugging an arm32 system on qemu, I found sometimes the single-step command (stepi) is not working. This can be reproduced by below steps: 1) start qemu-system-arm -s -S .. and wait for gdb connection. 2) start gdb and connect to qemu. In my case, gdb gets a wrong value (0x60) for PC. 3) After connected, type 'stepi' and expect it will stop at next ins. But, it has never stopped. This because: 1) We doesn't report =E2=80=98vContSupported=E2=80=99 feature to gdb expli= citly and gdb think we do not support it. In this case, gdb use a software breakpoint to emulate single-step. 2) Since gdb gets a wrong initial value of PC, then gdb inserts a breakpoint to wrong place (PC+4). Since we do support =E2=80=98vContSupported=E2=80=99 query command, so let'= s tell gdb that we support it. Before this change, gdb send below 'Z0' packet to implement single-step: gdb_handle_packet: Z0,4,4 After this change, gdb send "vCont;s.." which is expected: gdb_handle_packet: vCont? put_packet: vCont;c;C;s;S gdb_handle_packet: vCont;s:p1.1;c:p1.-1 Signed-off-by: Changbin Du Tested-by: Philippe Mathieu-Daud=C3=A9 --- gdbstub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gdbstub.c b/gdbstub.c index ce304ff482..adccd938e2 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -2111,7 +2111,7 @@ static void handle_query_supported(GdbCmdContext *gdb= _ctx, void *user_ctx) gdb_ctx->s->multiprocess =3D true; } =20 - pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), ";multiprocess+"); + pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), ";vContSupported+;= multiprocess+"); put_packet(gdb_ctx->s, gdb_ctx->str_buf); } =20 --=20 2.25.0