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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 B8FEFC19437 for ; Sat, 5 Dec 2020 18:19:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99894230FD for ; Sat, 5 Dec 2020 18:19:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730124AbgLESTy (ORCPT ); Sat, 5 Dec 2020 13:19:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728047AbgLERzF (ORCPT ); Sat, 5 Dec 2020 12:55:05 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 558D2C02B8FC; Sat, 5 Dec 2020 08:25:03 -0800 (PST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1607185158; 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=1FFJXTlgaPHPlq6JWR5jS6UY7uzh0dgGC/bjFp+gbqs=; b=nNQoqrajM4mtTtRcF4zjUNShWLzosjUuF6Dq5zJws3xqTuorL0/J5XmBRONWGCs0HkMshG QucEVw6SpX+2R4I3BcxcwOdtywz/FteHm0+FmriPyLOHLyWhufgRILYpWWyfDcN1fx9TPC AtM9vLxfx/tnHZ4HwuDkaNb9i6mlUcfUDgOF7tTVylSjE1qW+t2Ld8UupZNmLXwVZ7EyjR 1ODR/p+NvYzrHI8FbI1c72BAFsQU4qTenwqmzQfRdIVPlM8m24OhTTuYa4ate441pnR/3h u+K0bg8duDCOHGDKDUaqrZbZnZkfZ9ruCX75CzLPPYRKsapY9zmW7qZ2RCer4w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1607185158; 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=1FFJXTlgaPHPlq6JWR5jS6UY7uzh0dgGC/bjFp+gbqs=; b=YGJ7VAeVnR3FO93VpAq1Z2Jq1Qn7TDFMCAN/z+cTtrHFilQiMFhSsX0w4Qo8oNz5+eO9Kh 2Fq+x4fOajQ+E1BA== To: Oleksandr Natalenko , bugzilla-daemon@bugzilla.kernel.org Cc: 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. In-Reply-To: <20201204201930.vtvitsq6xcftjj3o@spock.localdomain> References: <20201204201930.vtvitsq6xcftjj3o@spock.localdomain> Date: Sat, 05 Dec 2020 17:19:18 +0100 Message-ID: <87zh2s8buh.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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); + return ret; +} + #ifdef CONFIG_HANDLE_DOMAIN_IRQ /** * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain