From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56716) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bRcfg-0001Gt-IW for qemu-devel@nongnu.org; Mon, 25 Jul 2016 05:59:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bRcff-0007B2-AV for qemu-devel@nongnu.org; Mon, 25 Jul 2016 05:59:36 -0400 From: Igor Mammedov Date: Mon, 25 Jul 2016 11:59:20 +0200 Message-Id: <1469440764-61619-3-git-send-email-imammedo@redhat.com> In-Reply-To: <1469440764-61619-1-git-send-email-imammedo@redhat.com> References: <1469440764-61619-1-git-send-email-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH v2 2/6] 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 --- v2: replace setting tqe_prev to NULL in generic QTAIL_REMOVE with a check and cleanup in cpu_exec_exit() to be on safe side. And delay QTAIL_REMOVE() change to 2.8. --- exec.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/exec.c b/exec.c index 2f57c62..ae45a70 100644 --- a/exec.c +++ b/exec.c @@ -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(); -- 2.7.4