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 0CE02C41535 for ; Mon, 9 May 2022 16:15:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238938AbiEIQTJ (ORCPT ); Mon, 9 May 2022 12:19:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238901AbiEIQTF (ORCPT ); Mon, 9 May 2022 12:19:05 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5571527A8A0; Mon, 9 May 2022 09:15:09 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DF6E2153B; Mon, 9 May 2022 09:15:08 -0700 (PDT) Received: from [10.57.1.248] (unknown [10.57.1.248]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 15C183F73D; Mon, 9 May 2022 09:14:59 -0700 (PDT) Message-ID: Date: Mon, 9 May 2022 17:14:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH 09/30] coresight: cpu-debug: Replace mutex with mutex_trylock on panic notifier To: "Guilherme G. Piccoli" , akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Leo Yan , Mathieu Poirier , Mike Leach References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-10-gpiccoli@igalia.com> <3cafe4fd-8a0b-2633-44a3-2995abd6c38c@arm.com> <65f24bc5-2211-0139-ee12-b2608e81ceb1@igalia.com> From: Suzuki K Poulose In-Reply-To: <65f24bc5-2211-0139-ee12-b2608e81ceb1@igalia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi On 09/05/2022 14:09, Guilherme G. Piccoli wrote: > On 28/04/2022 05:11, Suzuki K Poulose wrote: >> Hi Guilherme, >> >> On 27/04/2022 23:49, Guilherme G. Piccoli wrote: >>> The panic notifier infrastructure executes registered callbacks when >>> a panic event happens - such callbacks are executed in atomic context, >>> with interrupts and preemption disabled in the running CPU and all other >>> CPUs disabled. That said, mutexes in such context are not a good idea. >>> >>> This patch replaces a regular mutex with a mutex_trylock safer approach; >>> given the nature of the mutex used in the driver, it should be pretty >>> uncommon being unable to acquire such mutex in the panic path, hence >>> no functional change should be observed (and if it is, that would be >>> likely a deadlock with the regular mutex). >>> >>> Fixes: 2227b7c74634 ("coresight: add support for CPU debug module") >>> Cc: Leo Yan >>> Cc: Mathieu Poirier >>> Cc: Mike Leach >>> Cc: Suzuki K Poulose >>> Signed-off-by: Guilherme G. Piccoli >> >> How would you like to proceed with queuing this ? I am happy >> either way. In case you plan to push this as part of this >> series (I don't see any potential conflicts) : >> >> Reviewed-by: Suzuki K Poulose > > Hi Suzuki, some other maintainers are taking the patches to their next > branches for example. I'm working on V2, and I guess in the end would be > nice to reduce the size of the series a bit. > > So, do you think you could pick this one for your coresight/next branch > (or even for rc cycle, your call - this is really a fix)? > This way, I won't re-submit this one in V2, since it's gonna be merged > already in your branch. I have queued this to coresight/next. Thanks Suzuki