From 12051d82f004024d5d0202279be898c7b38cea56 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 23 Mar 2018 15:29:48 +0000 Subject: [PATCH] chardev/char-fe: Allow NULL chardev in qemu_chr_fe_init() 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 Signed-off-by: Peter Maydell Message-Id: <20180323152948.27048-1-peter.maydell@linaro.org> Signed-off-by: Paolo Bonzini --- chardev/char-fe.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/chardev/char-fe.c b/chardev/char-fe.c index 392db78b13..b1f228e8b5 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -198,19 +198,21 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp) { 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; -- 2.11.4.GIT