From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 720CFC433F5 for ; Sun, 9 Oct 2022 17:50:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230087AbiJIRuV (ORCPT ); Sun, 9 Oct 2022 13:50:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230101AbiJIRuU (ORCPT ); Sun, 9 Oct 2022 13:50:20 -0400 Received: from smtp-fw-9103.amazon.com (smtp-fw-9103.amazon.com [207.171.188.200]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85BC5DFB4; Sun, 9 Oct 2022 10:50:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1665337818; x=1696873818; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=1w/EVmNT7psEnsmxWuhy+bUOj1fiP2N+jrdt5vLYEOY=; b=QAJxXejz1Peoqowrf4/LrE4r8LlcIUyiXtieCZpilCGL1nVWbmNrlxEr mDGQaDAdXqnboGyjTlYJu0S4NNouinoLQVRy0gT76Z6yiHY6Z3fByImb7 RfCn4HLz190FfZ76zp8yH2y4Z5TtWkOpHdm4tHhsvsqkZVggCwmFr77VS E=; X-IronPort-AV: E=Sophos;i="5.95,172,1661817600"; d="scan'208";a="1062316103" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-pdx-2c-7d0c7241.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-9103.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2022 17:50:18 +0000 Received: from EX13MTAUWC002.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2c-7d0c7241.us-west-2.amazon.com (Postfix) with ESMTPS id E582B45618; Sun, 9 Oct 2022 17:50:17 +0000 (UTC) Received: from EX19D002UWC004.ant.amazon.com (10.13.138.186) by EX13MTAUWC002.ant.amazon.com (10.43.162.240) with Microsoft SMTP Server (TLS) id 15.0.1497.38; Sun, 9 Oct 2022 17:50:17 +0000 Received: from [192.168.22.91] (10.43.160.95) by EX19D002UWC004.ant.amazon.com (10.13.138.186) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.12; Sun, 9 Oct 2022 17:50:16 +0000 Message-ID: Date: Sun, 9 Oct 2022 10:50:15 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.3.2 Subject: Re: [PATCH 0/6] IRQ handling patches backport to 4.14 stable Content-Language: en-US To: "Herrenschmidt, Benjamin" , "gregkh@linuxfoundation.org" CC: "sashal@kernel.org" , "tglx@linutronix.de" , "stable@vger.kernel.org" , "mingo@redhat.com" , "linux-kernel@vger.kernel.org" , "Bacco, Mike" References: <20220929210651.12308-1-risbhat@amazon.com> <58294d242fc256a48abb31926232565830197f02.camel@amazon.com> From: "Bhatnagar, Rishabh" In-Reply-To: <58294d242fc256a48abb31926232565830197f02.camel@amazon.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.43.160.95] X-ClientProxiedBy: EX13D03UWA004.ant.amazon.com (10.43.160.250) To EX19D002UWC004.ant.amazon.com (10.13.138.186) Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 10/6/22 8:07 PM, Herrenschmidt, Benjamin wrote: > (putting my @amazon.com hat on) > > On Sun, 2022-10-02 at 17:30 +0200, Greg KH wrote: > > >> On Thu, Sep 29, 2022 at 09:06:45PM +0000, Rishabh Bhatnagar wrote: >>> This patch series backports a bunch of patches related IRQ handling >>> with respect to freeing the irq line while IRQ is in flight at CPU >>> or at the hardware level. >>> Recently we saw this issue in serial 8250 driver where the IRQ was >>> being >>> freed while the irq was in flight or not yet delivered to the CPU. >>> As a >>> result the irqchip was going into a wedged state and IRQ was not >>> getting >>> delivered to the cpu. These patches helped fixed the issue in 4.14 >>> kernel. >> Why is the serial driver freeing an irq while the system is running? >> Ah, this could happen on a tty hangup, right? > Right. Rishabh answered that separately. > >>> Let us know if more patches need backporting. >> What hardware platform were these patches tested on to verify they >> work properly?  And why can't they move to 4.19 or newer if they >> really need this fix?  What's preventing that? >> >> As Amazon doesn't seem to be testing 4.14.y -rc releases, I find it >> odd that you all did this backport.  Is this a kernel that you all >> care about? > These were tested on a collection of EC2 instances, virtual and metal I > believe (Rishabh, please confirm). Yes these patches were tested on multiple virt/metal EC2 instances. > > Amazon Linux 2 runs 4.14 or 5.10. Unfortunately we still have to > support customers running the former. > > We'll be including these patches in our releases, we thought it would > be nice to have them in -stable as well for the sake of whoever else > might be still using this kernel. No huge deal if they don't. > > As for testing -rc's, yes, we need to get better at that (and publish > what we test). Point taken :-) > > Cheers, > Ben. >