From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755687AbbLXPoL (ORCPT ); Thu, 24 Dec 2015 10:44:11 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51444 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753519AbbLXPmc (ORCPT ); Thu, 24 Dec 2015 10:42:32 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jan Stancek" , "Corey Minyard" , "Tony Camuso" Date: Thu, 24 Dec 2015 15:37:42 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 52/77] ipmi: move timer init to before irq is setup In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Stancek commit 27f972d3e00b50639deb4cc1392afaeb08d3cecc upstream. We encountered a panic on boot in ipmi_si on a dell per320 due to an uninitialized timer as follows. static int smi_start_processing(void *send_info, ipmi_smi_t intf) { /* Try to claim any interrupts. */ if (new_smi->irq_setup) new_smi->irq_setup(new_smi); --> IRQ arrives here and irq handler tries to modify uninitialized timer which triggers BUG_ON(!timer->function) in __mod_timer(). Call Trace: [] start_new_msg+0x47/0x80 [ipmi_si] [] start_check_enables+0x4e/0x60 [ipmi_si] [] smi_event_handler+0x1e8/0x640 [ipmi_si] [] ? __rcu_process_callbacks+0x54/0x350 [] si_irq_handler+0x3c/0x60 [ipmi_si] [] handle_IRQ_event+0x60/0x170 [] handle_edge_irq+0xde/0x180 [] handle_irq+0x49/0xa0 [] do_IRQ+0x6c/0xf0 [] ret_from_intr+0x0/0x11 /* Set up the timer that drives the interface. */ setup_timer(&new_smi->si_timer, smi_timeout, (long)new_smi); The following patch fixes the problem. To: Openipmi-developer@lists.sourceforge.net To: Corey Minyard CC: linux-kernel@vger.kernel.org Signed-off-by: Jan Stancek Signed-off-by: Tony Camuso Signed-off-by: Corey Minyard [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/char/ipmi/ipmi_si_intf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/char/ipmi/ipmi_si_intf.c +++ b/drivers/char/ipmi/ipmi_si_intf.c @@ -1148,15 +1148,15 @@ static int smi_start_processing(void new_smi->intf = intf; - /* Try to claim any interrupts. */ - if (new_smi->irq_setup) - new_smi->irq_setup(new_smi); - /* Set up the timer that drives the interface. */ setup_timer(&new_smi->si_timer, smi_timeout, (long)new_smi); new_smi->last_timeout_jiffies = jiffies; mod_timer(&new_smi->si_timer, jiffies + SI_TIMEOUT_JIFFIES); + /* Try to claim any interrupts. */ + if (new_smi->irq_setup) + new_smi->irq_setup(new_smi); + /* * Check if the user forcefully enabled the daemon. */