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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 330D8C2D0E4 for ; Sat, 5 Dec 2020 18:43:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E9E222E00 for ; Sat, 5 Dec 2020 18:43:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727247AbgLESnJ (ORCPT ); Sat, 5 Dec 2020 13:43:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727301AbgLEQ4O (ORCPT ); Sat, 5 Dec 2020 11:56:14 -0500 Received: from vulcan.natalenko.name (vulcan.natalenko.name [IPv6:2001:19f0:6c00:8846:5400:ff:fe0c:dfa0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF674C02A181; Sat, 5 Dec 2020 08:30:12 -0800 (PST) Received: from localhost (home.natalenko.name [151.237.229.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id 143D98C5EF8; Sat, 5 Dec 2020 17:24:04 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1607185444; 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=GK1PlK9w+nRMGOMB2nAyoVtDY3FO7kDEwHLHCW8nhA4=; b=iQeJiu7i/J2REiY0NP5gViG9pXMAflZwOOLWauV7OcFN7IsZqGt3kPudD6ohc6vbbp3fp0 CCbiBkbXBrnOGVg21+GRS1wTFXbzMdo0TvcUZP0y6SBD81klOVGRbFhQvleWZ6noko+1VY gejBdQqT9nF2LhSTprt93n5ZlWy6d3U= Date: Sat, 5 Dec 2020 17:24:03 +0100 From: Oleksandr Natalenko To: Thomas Gleixner Cc: bugzilla-daemon@bugzilla.kernel.org, jdelvare@suse.de, wsa@kernel.org, benjamin.tissoires@redhat.com, rui.zhang@intel.com, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Marc Zyngier , Peter Zijlstra , Carlos Jimenez Subject: Re: [Bug 202453] TRACE irq/18-i801_smb Tainted when enabled threadirqs in kernel commandline. Message-ID: <20201205162403.sey33v2js2cs65q4@spock.localdomain> References: <20201204201930.vtvitsq6xcftjj3o@spock.localdomain> <87zh2s8buh.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87zh2s8buh.fsf@nanos.tec.linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 05, 2020 at 05:19:18PM +0100, Thomas Gleixner wrote: > On Fri, Dec 04 2020 at 21:19, Oleksandr Natalenko wrote: > > On Thu, Dec 03, 2020 at 07:04:00PM +0000, bugzilla-daemon@bugzilla.kernel.org wrote: > >> 2) Have a wrapper around handle_generic_irq() which ensures that > >> interrupts are disabled before invoking it. > > > The question is whether it's guaranteed under all circumstances > > including forced irq threading. The i801 driver has assumptions about > > this, so I wouldn't be surprised if there are more. > > Assuming that a final answer might take some time, the below which > implements #2 will make it at least work for now. > > Thanks, > > tglx > --- > Subject: genirq, i2c: Provide and use generic_dispatch_irq() > From: Thomas Gleixner > Date: Thu, 03 Dec 2020 19:12:24 +0100 > > Carlos reported that on his system booting with 'threadirqs' on the command > line result in the following warning: > > irq 31 handler irq_default_primary_handler+0x0/0x10 enabled interrupts > WARNING: CPU: 2 PID: 989 at kernel/irq/handle.c:153 __handle_irq_event_percpu+0x19f/0x1b0 > > The reason is in the i2c stack: > > i801_isr() > i801_host_notify_isr() > i2c_handle_smbus_host_notify() > generic_handle_irq() > > and that explodes with forced interrupt threading because it's called with > interrupts enabled. > > It would be possible to set IRQF_NO_THREAD on the i801 interrupt to exclude > it from force threading, but that would break on RT and require a larger > update. > > It's also unclear whether there are other drivers which can reach that code > path via i2c_slave_host_notify_cb(). As there are enough i2c drivers which > use threaded interrupt handlers by default it seems not completely > impossible that this can happen even without force threaded interrupts. > > For a quick fix provide a wrapper around generic_handle_irq() which has a > local_irq_save/restore() around the invocation and use it in the i2c code. > > Reported-by: Carlos Jimenez > Signed-off-by: Thomas Gleixner > Link: https://bugzilla.kernel.org/show_bug.cgi?id=202453 > --- > drivers/i2c/i2c-core-base.c | 2 +- > include/linux/irqdesc.h | 1 + > kernel/irq/irqdesc.c | 20 ++++++++++++++++++++ > 3 files changed, 22 insertions(+), 1 deletion(-) > > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -1385,7 +1385,7 @@ int i2c_handle_smbus_host_notify(struct > if (irq <= 0) > return -ENXIO; > > - generic_handle_irq(irq); > + generic_dispatch_irq(irq); > > return 0; > } > --- a/include/linux/irqdesc.h > +++ b/include/linux/irqdesc.h > @@ -153,6 +153,7 @@ static inline void generic_handle_irq_de > } > > int generic_handle_irq(unsigned int irq); > +int generic_dispatch_irq(unsigned int irq); > > #ifdef CONFIG_HANDLE_DOMAIN_IRQ > /* > --- a/kernel/irq/irqdesc.c > +++ b/kernel/irq/irqdesc.c > @@ -652,6 +652,26 @@ int generic_handle_irq(unsigned int irq) > } > EXPORT_SYMBOL_GPL(generic_handle_irq); > > +/** > + * generic_dispatch_irq - Dispatch an interrupt from an interrupt handler > + * @irq: The irq number to handle > + * > + * A wrapper around generic_handle_irq() which ensures that interrupts are > + * disabled when the primary handler of the dispatched irq is invoked. > + * This is useful for interrupt handlers with dispatching to be safe for > + * the forced threaded case. > + */ > +int generic_dispatch_irq(unsigned int irq) > +{ > + unsigned long flags; > + int ret; > + > + local_irq_save(&flags); > + ret = generic_handle_irq(irq); > + local_irq_restore(&flags); FWIW, for me &flags explodes build on v5.10-rc6. I had to change it to local_irq_save/restore(flags) (without taking an address via &). > + return ret; > +} > + > #ifdef CONFIG_HANDLE_DOMAIN_IRQ > /** > * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain -- Oleksandr Natalenko (post-factum)