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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2420DC433E1 for ; Mon, 22 Mar 2021 11:40:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D132B6199F for ; Mon, 22 Mar 2021 11:40:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230190AbhCVLju (ORCPT ); Mon, 22 Mar 2021 07:39:50 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:53608 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230012AbhCVLjX (ORCPT ); Mon, 22 Mar 2021 07:39:23 -0400 Date: Mon, 22 Mar 2021 12:39:18 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1616413160; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5ZhX+YE/qD6wm9rEUpODyk3JBhUspUq04ONWRA919tI=; b=DLf5/KRpvDoWIs85QD34KKZvMM/CGNjcRxRY3lF40GhFLoSYDDk6UwtmSdXqYqPqT5SFcq 1kNJ+FbthHV/MpYxlQDutpf9KNfcekne/v9jsAk9/MGkFngNtAN9PN3Ke/TMlPVPKDvom/ PdyIJSuCfZRCZnnb4KdXFX/owtIz58bE/Nkz6N4RvxWepBCnun65qMkRS6b2dzhrFXCflF VPbG/2BtSJPYLqYXuJCKC3fOazIQK9pxiQFnW0ddSBT1+F3/1r9yQeEruAtN3JovHR99HH tJIGSKzBG5UWLccY10hOcBYO8qxt/vb1epxPVMkRTWH+ePNF4J9lNOli7+Xn6A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1616413160; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5ZhX+YE/qD6wm9rEUpODyk3JBhUspUq04ONWRA919tI=; b=lviYqnUjfYbaYCagkQiljIDSUmTIThsm8Y5+YPECy0rY8ZuMD5rQlw4Yp9vyLOhYSuTeQo 4oUDDcSx+Fb95fCA== From: Sebastian Andrzej Siewior To: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= Cc: Johan Hovold , Greg Kroah-Hartman , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Sam Nobs , Thomas Gleixner , Peter Zijlstra Subject: Re: [PATCH] serial: imx: drop workaround for forced irq threading Message-ID: <20210322113918.ze52gq54cpsspgej@linutronix.de> References: <20210322111036.31966-1-johan@kernel.org> <20210322113402.naqzgkoe2xesnw4b@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20210322113402.naqzgkoe2xesnw4b@pengutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-03-22 12:34:02 [+0100], Uwe Kleine-K=C3=B6nig wrote: > On Mon, Mar 22, 2021 at 12:10:36PM +0100, Johan Hovold wrote: > > Force-threaded interrupt handlers used to run with interrupts enabled, > > something which could lead to deadlocks in case a threaded handler > > shared a lock with code running in hard interrupt context (e.g. timer > > callbacks) and did not explicitly disable interrupts. > >=20 > > This was specifically the case for serial drivers that take the port > > lock in their console write path as printk can be called from hard > > interrupt context also with forced threading ("threadirqs"). > >=20 > > Since commit 81e2073c175b ("genirq: Disable interrupts for force > > threaded handlers") interrupt handlers always run with interrupts > > disabled on non-RT so that drivers no longer need to do handle this. >=20 > So we're breaking RT knowingly here? If this is the case I'm not happy > with your change. (And if RT is not affected a different wording would > be good.) Which wording, could you be more specific? It looks good from here and no, RT is not affected. > Best regards > Uwe Sebastian