All the functions in char-fe.c handle the CharBackend
having a NULL Chardev pointer, which means that the
backend exists but is not connected to anything. The
exception is qemu_chr_fe_init(), which will crash if
passed a NULL Chardev pointer argument. This can happen
for various boards if they're started with 'nodefaults':
arm-softmmu/qemu-system-arm -S -nodefaults -M cubieboard
riscv32-softmmu/qemu-system-riscv32 -nodefaults -M sifive_e
Make qemu_chr_fe_init() accept a NULL chardev. This allows
UART models to handle NULL chardev properties without
generally needing to special case them or to manually
create a NullChardev.
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <
20180323152948.27048-1-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
{
int tag = 0;
- if (CHARDEV_IS_MUX(s)) {
- MuxChardev *d = MUX_CHARDEV(s);
+ if (s) {
+ if (CHARDEV_IS_MUX(s)) {
+ MuxChardev *d = MUX_CHARDEV(s);
+
+ if (d->mux_cnt >= MAX_MUX) {
+ goto unavailable;
+ }
- if (d->mux_cnt >= MAX_MUX) {
+ d->backends[d->mux_cnt] = b;
+ tag = d->mux_cnt++;
+ } else if (s->be) {
goto unavailable;
+ } else {
+ s->be = b;
}
-
- d->backends[d->mux_cnt] = b;
- tag = d->mux_cnt++;
- } else if (s->be) {
- goto unavailable;
- } else {
- s->be = b;
}
b->fe_open = false;