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 AD3EAC433EF for ; Mon, 24 Jan 2022 16:26:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243715AbiAXQ0d (ORCPT ); Mon, 24 Jan 2022 11:26:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241129AbiAXQ0a (ORCPT ); Mon, 24 Jan 2022 11:26:30 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AB8AC06173B for ; Mon, 24 Jan 2022 08:26:30 -0800 (PST) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1643041587; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jooe9jBPXibapFbfnxQ9Av5bLAmMuo5zROFe8iN25sY=; b=iFsT4KKmlgDvY2sYKUcXLLyhxqrq1Q7RKdyP39BiRc3sfQgRDuidwLq867y1P5clkBsry1 00Oigt05jpcHFVOIxHBdzTeq5WBV/vwzcRZX7oMbiyS1lx/Uw3W9lwekXxtBXSyLC60GYz aWg+jpQz9K1bk4cRrGOWIyvYjTkzNHwmJ+2ywWUAHwYXGqWXnrBo7PbebH6h+Z9S7FJx3M CFyFq++qZitMkmdxD2Yts8QtjK0r7687PzKekQxUa1yA9/qiAQuGlzoTwp4YgBShiRhpOG 7acPyNAEcttIGD9x9OJ01cgIez44A/J2vs6SeYstU+9r60Ow04i77aP54gzCwQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1643041587; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jooe9jBPXibapFbfnxQ9Av5bLAmMuo5zROFe8iN25sY=; b=6dzMQhWUss8oyS0GWwz2l/IXUPpbT8WqibCSs2Oh7xUYiw43zIcmpXnPFE+jF2mIfWF2FX 6uHGqZAG5Ztl7EDg== To: Stephen Brennan , Petr Mladek , Sergey Senozhatsky , Steven Rostedt Cc: Stephen Brennan , Sergey Senozhatsky , linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] printk: Drop console_sem during panic In-Reply-To: <87pmoh3yf9.fsf@jogness.linutronix.de> References: <20220121190222.572694-1-stephen.s.brennan@oracle.com> <20220121190222.572694-5-stephen.s.brennan@oracle.com> <87pmoh3yf9.fsf@jogness.linutronix.de> Date: Mon, 24 Jan 2022 17:32:27 +0106 Message-ID: <87mtjl3xsc.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022-01-24, John Ogness wrote: > Something like: > > @@ -2731,7 +2731,8 @@ void console_unlock(void) > * there's a new owner and the console_unlock() from them will do the > * flush, no worries. > */ > - retry = prb_read_valid(prb, next_seq, NULL); > + retry = (pcpu != raw_smp_processor_id()) && > + prb_read_valid(prb, next_seq, NULL); > if (retry && console_trylock()) > goto again; > } Sorry, that hunk is obviously garbage. I meant something like: @@ -2731,7 +2731,10 @@ void console_unlock(void) * there's a new owner and the console_unlock() from them will do the * flush, no worries. */ - retry = prb_read_valid(prb, next_seq, NULL); + if (panic_in_progress()) + retry = (pcpu == raw_smp_processor_id()) && prb_read_valid(prb, next_seq, NULL); + else + retry = prb_read_valid(prb, next_seq, NULL); if (retry && console_trylock()) goto again; } I'm sure there is a cleaner way to code that. John