From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264138AbUDRFn7 (ORCPT ); Sun, 18 Apr 2004 01:43:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264139AbUDRFn7 (ORCPT ); Sun, 18 Apr 2004 01:43:59 -0400 Received: from gate.crashing.org ([63.228.1.57]:46487 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S264138AbUDRFnx (ORCPT ); Sun, 18 Apr 2004 01:43:53 -0400 Subject: [PATCH] ppc64: Fix CPU hot unplug deadlock From: Benjamin Herrenschmidt To: Andrew Morton Cc: Linus Torvalds , Linux Kernel list Content-Type: text/plain Message-Id: <1082266707.2135.325.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Sun, 18 Apr 2004 15:38:27 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi ! My RTAS locking fixes incorrectly added a spinlock around the function used to stop a CPU, that function never returns, thus the lock becomes stale. The correct fix is to disable interrupts instead (the RTAS params beeing per-CPU, this should be safe enough) Ben. diff -urN linux-2.5/arch/ppc64/kernel/rtas.c ppc64-linux-2.5/arch/ppc64/kernel/rtas.c --- linux-2.5/arch/ppc64/kernel/rtas.c 2004-04-17 12:39:03.253986984 +1000 +++ ppc64-linux-2.5/arch/ppc64/kernel/rtas.c 2004-04-18 15:35:41.871029480 +1000 @@ -504,9 +504,9 @@ void rtas_stop_self(void) { struct rtas_args *rtas_args = &(get_paca()->xRtas); - unsigned long s; - spin_lock_irqsave(&rtas.lock, s); + local_irq_disable(s); + rtas_args->token = rtas_token("stop-self"); BUG_ON(rtas_args->token == RTAS_UNKNOWN_SERVICE); rtas_args->nargs = 0; @@ -516,7 +516,6 @@ printk("%u %u Ready to die...\n", smp_processor_id(), hard_smp_processor_id()); enter_rtas((void *)__pa(rtas_args)); - spin_unlock_irqrestore(&rtas.lock, s); panic("Alas, I survived.\n"); }