From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757465AbZFPLTu (ORCPT ); Tue, 16 Jun 2009 07:19:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755164AbZFPLTm (ORCPT ); Tue, 16 Jun 2009 07:19:42 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:39799 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755070AbZFPLTl (ORCPT ); Tue, 16 Jun 2009 07:19:41 -0400 Date: Tue, 16 Jun 2009 16:49:41 +0530 From: Ananth N Mavinakayanahalli To: heiko.carstens@de.ibm.com, rusty@rustcorp.com.au Cc: lkml Subject: [PATCH] stop_cpu() needs to use raw_smp_processor_id() Message-ID: <20090616111941.GA3287@in.ibm.com> Reply-To: ananth@in.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With DEBUG_PREEMPT on, on an s390 box, we are seeing: BUG: using smp_processor_id() in preemptible [00000000] code: insmod/3006 caller is arch_arm_kprobe+0x2c/0x90 CPU: 0 Not tainted 2.6.30-rc8-tipjun10-02053-g39ae214 #7 Process insmod (pid: 3006, task: 000000007df31410, ksp: 000000007e087a28) 0000000000000000 000000007e087c38 0000000000000002 0000000000000000 000000007e087cd8 000000007e087c50 000000007e087c50 0000000000048156 00000000003e4de8 000000000002b830 0000000000000000 0000000000000000 0000000000000000 000000007e087c38 ffffffff0000000d 000000007e087ca8 000000000040a780 000000000001635c 000000007e087c38 000000007e087c80 Call Trace: ([<00000000000162e6>] show_trace+0x13a/0x148) [<00000000001f123a>] debug_smp_processor_id+0x136/0x13c [<00000000003ddbd8>] arch_arm_kprobe+0x2c/0x90 [<00000000003df8cc>] register_kprobe+0x630/0x684 [<000003e000241056>] kprobe_init+0x56/0xa8 [kprobe_example] [<00000000000120c2>] do_one_initcall+0x3e/0x16c [<000000000007cb4c>] SyS_init_module+0xc4/0x1fc [<0000000000027f42>] sysc_noemu+0x10/0x16 [<0000004a4493324e>] 0x4a4493324e Digging further this seems to be due to stop_cpu(). Shouldn't stop_cpu() be using raw_smp_processor_id()? Signed-off-by: Ananth N Mavinakayanahalli --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6.30/kernel/stop_machine.c =================================================================== --- linux-2.6.30.orig/kernel/stop_machine.c +++ linux-2.6.30/kernel/stop_machine.c @@ -68,7 +68,7 @@ static void stop_cpu(struct work_struct { enum stopmachine_state curstate = STOPMACHINE_NONE; struct stop_machine_data *smdata = &idle; - int cpu = smp_processor_id(); + int cpu = raw_smp_processor_id(); int err; if (!active_cpus) {