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 <imamm...@redhat.com> Reported-by: David Gibson <da...@gibson.dropbear.id.au> --- include/qemu/queue.h | 2 ++ exec.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/qemu/queue.h b/include/qemu/queue.h index c2b6c81..2c2c74b 100644 --- a/include/qemu/queue.h +++ b/include/qemu/queue.h @@ -407,6 +407,7 @@ struct { \ else \ (head)->tqh_last = (elm)->field.tqe_prev; \ *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ + (elm)->field.tqe_prev = NULL; \ } while (/*CONSTCOND*/0) #define QTAILQ_FOREACH(var, head, field) \ @@ -430,6 +431,7 @@ struct { \ #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) #define QTAILQ_FIRST(head) ((head)->tqh_first) #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) +#define QTAILQ_IN_USE(elm, field) ((elm)->field.tqe_prev) #define QTAILQ_LAST(head, headname) \ (*(((struct headname *)((head)->tqh_last))->tqh_last)) diff --git a/exec.c b/exec.c index 2f57c62..8c5da32 100644 --- a/exec.c +++ b/exec.c @@ -643,8 +643,8 @@ 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 (!QTAILQ_IN_USE(cpu, node)) { + /* there is nothing to undo since cpu_exec_init() hasn't been called */ cpu_list_unlock(); return; } -- 2.7.4