Commit 8b1b8350 authored Jul 25, 2016 by Igor Mammedov Committed by Eduardo Habkost Jul 26, 2016

exec: Don't use cpu_index to detect if cpu_exec_init()'s been called



Instead use QTAIL's tqe_prev field to detect if cpu's been
placed in list by cpu_exec_init() which is always set if
QTAIL element is in list.

Fixes SIGSEGV on failure path in case cpu_index is assigned
by board and cpu.relalize() fails before cpu_exec_init() is called.

In follow up patches, cpu_index will be assigned by boards that
support cpu hot(un)plug and need stable cpu_index that doesn't
depend on order cpus are created/removed.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

parent 1bc7e522

exec.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -643,13 +643,14 @@ void cpu_exec_exit(CPUState *cpu)
		CPUClass *cc = CPU_GET_CLASS(cpu);

		cpu_list_lock();
		if (cpu->cpu_index == -1) {
		/* cpu_index was never allocated by this @cpu or was already freed. */
		if (cpu->node.tqe_prev == NULL) {
		/* there is nothing to undo since cpu_exec_init() hasn't been called */
		cpu_list_unlock();
		return;
		}

		QTAILQ_REMOVE(&cpus, cpu, node);
		cpu->node.tqe_prev = NULL;
		cpu_release_index(cpu);
		cpu->cpu_index = -1;
		cpu_list_unlock();