diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2023-07-11 18:59:03 +1000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2023-07-31 14:57:32 +0100 |
| commit | 108e8180c6b0c315711aa54e914030a313505c17 (patch) | |
| tree | 3e7b9626396c5b45067036e07e0519253b2bee07 /gdbstub | |
| parent | fe6bda58e083ec8ffa5c5166e3b1055501b6318a (diff) | |
gdbstub: Fix client Ctrl-C handling
The gdb remote protocol has a special interrupt character (0x03) that is
transmitted outside the regular packet processing, and represents a
Ctrl-C pressed in the client. Despite not being a regular packet, it
does expect a regular stop response if the stub successfully stops the
running program.
See: https://sourceware.org/gdb/onlinedocs/gdb/Interrupts.html
Inhibiting the stop reply packet can lead to gdb client hang. So permit
a stop response when receiving a character from gdb that stops the vm.
Additionally, add a warning if that was not a 0x03 character, because
the gdb session is likely to end up getting confused if this happens.
Cc: qemu-stable@nongnu.org
Fixes: 758370052fb ("gdbstub: only send stop-reply packets when allowed to")
Reported-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Message-id: 20230711085903.304496-1-npiggin@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'gdbstub')
| -rw-r--r-- | gdbstub/gdbstub.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index 6911b73c07..ce8b42eb15 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -2051,8 +2051,17 @@ void gdb_read_byte(uint8_t ch) return; } if (runstate_is_running()) { - /* when the CPU is running, we cannot do anything except stop - it when receiving a char */ + /* + * When the CPU is running, we cannot do anything except stop + * it when receiving a char. This is expected on a Ctrl-C in the + * gdb client. Because we are in all-stop mode, gdb sends a + * 0x03 byte which is not a usual packet, so we handle it specially + * here, but it does expect a stop reply. + */ + if (ch != 0x03) { + warn_report("gdbstub: client sent packet while target running\n"); + } + gdbserver_state.allow_stop_reply = true; vm_stop(RUN_STATE_PAUSED); } else #endif |