From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35935) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bQGJI-0002VY-3D for qemu-devel@nongnu.org; Thu, 21 Jul 2016 11:54:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bQGJG-0007ys-46 for qemu-devel@nongnu.org; Thu, 21 Jul 2016 11:54:51 -0400 From: Igor Mammedov Date: Thu, 21 Jul 2016 17:54:33 +0200 Message-Id: <1469116479-233280-3-git-send-email-imammedo@redhat.com> In-Reply-To: <1469116479-233280-1-git-send-email-imammedo@redhat.com> References: <1469116479-233280-1-git-send-email-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH 2/8] exec: don't use cpu_index to detect if cpu_exec_init()'s been called for cpu List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Peter Crosthwaite , Richard Henderson , Eduardo Habkost , "Michael S. Tsirkin" , David Gibson , Alexander Graf , Riku Voipio , Bharata B Rao , qemu-ppc@nongnu.org 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 Reported-by: David Gibson --- 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