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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 40C8AC433FE for ; Tue, 22 Nov 2022 13:35:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=K5psJqE4H7X36L5IfPFI8/mxkaFR3/avimUXtDPFVGw=; b=vkK9VZZ1MUdGW8 HS1GsB54oUeAnbMEuItHl/He/v5N0utAxJ5QkWhOS9Cs6ufMAmO5EbyoL97SpwyLm9lrV+dTB6MdW njb6vRn7lH8FPhRSLSKzOQqH50fZ0VFphLWY022N96D7vm/EhwCLY/yXqZSM25OqEC13LJ0UKvhL8 B3IEBzE2rsfmCwUQQnTCAB/qPhVQaFamL6oG+r4+jpmQNmRdL3rFd0K6Yb/PSYNXH/efWdCFeGH8o OuGwI/A2eSWoYMKmvgp33/ttVZ2AARh4EFTL7m78Ek6W4or+XIj1ErEHzN2SQs1lQsFsdXPlhloEf btnV0qaFgy4lcmABPyMQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxTRE-009fxi-74; Tue, 22 Nov 2022 13:35:48 +0000 Received: from fanzine2.igalia.com ([213.97.179.56]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxTRA-009fx4-Qz for kexec@lists.infradead.org; Tue, 22 Nov 2022 13:35:46 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=rSYIGGtjZljFBal86Avbxge1dAX05jgxf9qrktsTsB8=; b=MX800+aYXTdyYof4USzixvuPvg 9FbkPgWEf4yn5YKSZ6YZvZYMUIrJ83siHY3JDQnjBib+dAZOvIjPcv4rwFWWZmC8nuU/CNyqTv37J LI9uahtiyTlFT5sg3l2Jt6DAPlbV/eGuCYZHMx1mJgP8y9VUP0QV5AhKWiiwBT3/TtAdOZxoHUjGo wBjoV4n84SXGRfQJ1FQgM2titKAX9RMXtyQrLP2E1UPM76R5ywtg8b8JzSylFz4KM6CKbhsW2RDhw 2Wuo/c750D1OMJECUK35f1MTpZl3Tuqe5CqaKSXYSU2Si3ILxqlcvyZFxEYL6RqkDNw1VeQ19rA9/ QwSDYHeg==; Received: from [177.102.6.147] (helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1oxTR5-006yBT-L8; Tue, 22 Nov 2022 14:35:39 +0100 Message-ID: <831175d7-1b30-de61-d6c5-cbb91e4fdcfb@igalia.com> Date: Tue, 22 Nov 2022 10:35:34 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.2 Subject: Re: [PATCH V3 11/11] panic: Fixes the panic_print NMI backtrace setting Content-Language: en-US To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, feng.tang@intel.com Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net References: <20220819221731.480795-1-gpiccoli@igalia.com> <20220819221731.480795-12-gpiccoli@igalia.com> From: "Guilherme G. Piccoli" In-Reply-To: <20220819221731.480795-12-gpiccoli@igalia.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221122_053544_904083_A6D41439 X-CRM114-Status: GOOD ( 21.57 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 19/08/2022 19:17, Guilherme G. Piccoli wrote: > Commit 8d470a45d1a6 ("panic: add option to dump all CPUs backtraces in panic_print") > introduced a setting for the "panic_print" kernel parameter to allow > users to request a NMI backtrace on panic. Problem is that the panic_print > handling happens after the secondary CPUs are already disabled, hence > this option ended-up being kind of a no-op - kernel skips the NMI trace > in idling CPUs, which is the case of offline CPUs. > > Fix it by checking the NMI backtrace bit in the panic_print prior to > the CPU disabling function. > > Fixes: 8d470a45d1a6 ("panic: add option to dump all CPUs backtraces in panic_print") > Cc: Feng Tang > Cc: Petr Mladek > Signed-off-by: Guilherme G. Piccoli > > --- > > V3: > - No changes. > > V2: > - new patch, there was no V1 of this one. > > Hi folks, thanks upfront for reviews. This is a new patch, fixing an issue > I found in my tests, so I shoved it into this fixes series. > > Notice that while at it, I got rid of the "crash_kexec_post_notifiers" > local copy in panic(). This was introduced by commit b26e27ddfd2a > ("kexec: use core_param for crash_kexec_post_notifiers boot option"), > but it is not clear from comments or commit message why this local copy > is required. > > My understanding is that it's a mechanism to prevent some concurrency, > in case some other CPU modify this variable while panic() is running. > I find it very unlikely, hence I removed it - but if people consider > this copy needed, I can respin this patch and keep it, even providing a > comment about that, in order to be explict about its need. > > Let me know your thoughts! Cheers, > > Guilherme > > Hi folks, bi-monthly ping - apologies for the noise heh Is there anything suggested so we can get this fix merged in 6.2? Any suggestions / reviews are much appreciated. Tnx in advance, Guilherme _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec