On 23/03/2015 11:48, Peter Crosthwaite wrote:
> following a464982499b2f637f6699e3d03e0a9d2e0b5288b, it's now possible for
> there to be attempts to take the BQL before CPUs have been realized in
> cases where a machine model inits peripherals before the first CPU.
>
> BQL lock aquisition kicks the first_cpu, leading to a segfault if this
> happens pre-realize. Guard the CPU kick routine to perform no action for
> a CPU that doesn't exist or doesn't have a thread yet.
>
> There was a fix to this with commit
> 6b49809c597331803ea941eadda813e5bb4e8fe2, but the check there misses
> the case where the CPU has been inited and not realized. Strengthen the
> check to make sure that the first_cpu has a thread (i.e. it is
> realized) before allowing the kick.
>
> Signed-off-by: Peter Crosthwaite <peter.crosthwa...@xilinx.com>
> ---
> Fixed since V1:
> Change implementation to match 6b49809c597331803ea941eadda813e5bb4e8fe2
> ---
> cpus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/cpus.c b/cpus.c
> index 314df16..e6dcae3 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -1119,7 +1119,7 @@ bool qemu_in_vcpu_thread(void)
> void qemu_mutex_lock_iothread(void)
> {
> atomic_inc(&iothread_requesting_mutex);
> - if (!tcg_enabled() || !first_cpu) {
> + if (!tcg_enabled() || !first_cpu || !first_cpu->thread) {
> qemu_mutex_lock(&qemu_global_mutex);
> atomic_dec(&iothread_requesting_mutex);
> } else {
>
Thanks, applied.
Paolo
