Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939320AbdD1TxS (ORCPT ); Fri, 28 Apr 2017 15:53:18 -0400 Received: from mail-io0-f194.google.com ([209.85.223.194]:33536 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938084AbdD1TxK (ORCPT ); Fri, 28 Apr 2017 15:53:10 -0400 Reply-To: minyard@acm.org Subject: Re: [PATCH] ipmi/watchdog: fix wdog hang on panic waiting for ipmi response References: <20170420234947.1037-1-rlippert@google.com> To: Robert Lippert Cc: Robert Lippert , openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org From: Corey Minyard Message-ID: <9175e5aa-4fd7-4e25-8edd-a4b7460fcebb@acm.org> Date: Fri, 28 Apr 2017 14:53:06 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170420234947.1037-1-rlippert@google.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1972 Lines: 56 On 04/20/2017 06:49 PM, Robert Lippert wrote: > Commit c49c097610fe ("ipmi: Don't call receive handler in the > panic context") means that the panic_recv_free is not called during a > panic and the atomic count does not drop to 0. > > Fix this by only expecting one decrement of the atomic variable > which comes from panic_smi_free. Thanks, queued for the next kernel release. -corey > Signed-off-by: Robert Lippert > --- > > drivers/char/ipmi/ipmi_watchdog.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c > index 5ca24d9b101b..d165af8abe36 100644 > --- a/drivers/char/ipmi/ipmi_watchdog.c > +++ b/drivers/char/ipmi/ipmi_watchdog.c > @@ -516,7 +516,7 @@ static void panic_halt_ipmi_heartbeat(void) > msg.cmd = IPMI_WDOG_RESET_TIMER; > msg.data = NULL; > msg.data_len = 0; > - atomic_add(2, &panic_done_count); > + atomic_add(1, &panic_done_count); > rv = ipmi_request_supply_msgs(watchdog_user, > (struct ipmi_addr *) &addr, > 0, > @@ -526,7 +526,7 @@ static void panic_halt_ipmi_heartbeat(void) > &panic_halt_heartbeat_recv_msg, > 1); > if (rv) > - atomic_sub(2, &panic_done_count); > + atomic_sub(1, &panic_done_count); > } > > static struct ipmi_smi_msg panic_halt_smi_msg = { > @@ -550,12 +550,12 @@ static void panic_halt_ipmi_set_timeout(void) > /* Wait for the messages to be free. */ > while (atomic_read(&panic_done_count) != 0) > ipmi_poll_interface(watchdog_user); > - atomic_add(2, &panic_done_count); > + atomic_add(1, &panic_done_count); > rv = i_ipmi_set_timeout(&panic_halt_smi_msg, > &panic_halt_recv_msg, > &send_heartbeat_now); > if (rv) { > - atomic_sub(2, &panic_done_count); > + atomic_sub(1, &panic_done_count); > printk(KERN_WARNING PFX > "Unable to extend the watchdog timeout."); > } else {