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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 EABD7C2D0DB for ; Fri, 24 Jan 2020 11:25:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C12AA206D4 for ; Fri, 24 Jan 2020 11:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579865132; bh=WuuGUHllKEaRwTEewQ4s8Vxp9Zxuk3Sxd+JLm9SsTvg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HpkxdRl16iE/mfSyqsmVrODVY/Jfk6JMhyBfarG5hKVQIxBGGnubsQBMQgLthcEzM CsEYnbrZDE9bkKGxlg5nFmYryknG9bpLOxxOf6i5riQ0iK8ivIwm1ZTE8QQJcOU+bF DXZL0Nf5VrEyIeXb2CNdEP/70LqqjpIFClSuH40Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391395AbgAXLZb (ORCPT ); Fri, 24 Jan 2020 06:25:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:39574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391499AbgAXLZ3 (ORCPT ); Fri, 24 Jan 2020 06:25:29 -0500 Received: from localhost (ip-213-127-102-57.ip.prioritytelecom.net [213.127.102.57]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 539252075D; Fri, 24 Jan 2020 11:25:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579865128; bh=WuuGUHllKEaRwTEewQ4s8Vxp9Zxuk3Sxd+JLm9SsTvg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UZKju/xItapc3lJDGzxe6h6b0jZIsQ2ETOVoXLuu6vW79FUl75BI/Y76iwuK7gw1F yb++opzPFSFACTAjxJRBoDYEHfFo26/c83u3vIU+aYpgdZRQnZlNwC/GEPVqnKgSVt L4/Pbt57BkdkDGMFppld8hny7PS/g0OQa0VwHIJ0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jouni Malinen , Johannes Berg , Richard Weinberger , Sasha Levin Subject: [PATCH 4.19 461/639] um: Fix IRQ controller regression on console read Date: Fri, 24 Jan 2020 10:30:31 +0100 Message-Id: <20200124093144.965717733@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124093047.008739095@linuxfoundation.org> References: <20200124093047.008739095@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jouni Malinen [ Upstream commit bebe4681d0e7e1be2608282dc86645728bc7f623 ] The conversion of UML to use epoll based IRQ controller claimed that clone_one_chan() can safely call um_free_irq() while starting to ignore the delay_free_irq parameter that explicitly noted that the IRQ cannot be freed because this is being called from chan_interrupt(). This resulted in free_irq() getting called in interrupt context ("Trying to free IRQ 6 from IRQ context!"). Fix this by restoring previously used delay_free_irq processing. Fixes: ff6a17989c08 ("Epoll based IRQ controller") Signed-off-by: Jouni Malinen Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/chan_kern.c | 52 +++++++++++++++++++++++++++++++------ arch/um/kernel/irq.c | 4 +++ 2 files changed, 48 insertions(+), 8 deletions(-) diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c index 05588f9466c7f..13ba195f9c9c8 100644 --- a/arch/um/drivers/chan_kern.c +++ b/arch/um/drivers/chan_kern.c @@ -171,19 +171,55 @@ int enable_chan(struct line *line) return err; } +/* Items are added in IRQ context, when free_irq can't be called, and + * removed in process context, when it can. + * This handles interrupt sources which disappear, and which need to + * be permanently disabled. This is discovered in IRQ context, but + * the freeing of the IRQ must be done later. + */ +static DEFINE_SPINLOCK(irqs_to_free_lock); +static LIST_HEAD(irqs_to_free); + +void free_irqs(void) +{ + struct chan *chan; + LIST_HEAD(list); + struct list_head *ele; + unsigned long flags; + + spin_lock_irqsave(&irqs_to_free_lock, flags); + list_splice_init(&irqs_to_free, &list); + spin_unlock_irqrestore(&irqs_to_free_lock, flags); + + list_for_each(ele, &list) { + chan = list_entry(ele, struct chan, free_list); + + if (chan->input && chan->enabled) + um_free_irq(chan->line->driver->read_irq, chan); + if (chan->output && chan->enabled) + um_free_irq(chan->line->driver->write_irq, chan); + chan->enabled = 0; + } +} + static void close_one_chan(struct chan *chan, int delay_free_irq) { + unsigned long flags; + if (!chan->opened) return; - /* we can safely call free now - it will be marked - * as free and freed once the IRQ stopped processing - */ - if (chan->input && chan->enabled) - um_free_irq(chan->line->driver->read_irq, chan); - if (chan->output && chan->enabled) - um_free_irq(chan->line->driver->write_irq, chan); - chan->enabled = 0; + if (delay_free_irq) { + spin_lock_irqsave(&irqs_to_free_lock, flags); + list_add(&chan->free_list, &irqs_to_free); + spin_unlock_irqrestore(&irqs_to_free_lock, flags); + } else { + if (chan->input && chan->enabled) + um_free_irq(chan->line->driver->read_irq, chan); + if (chan->output && chan->enabled) + um_free_irq(chan->line->driver->write_irq, chan); + chan->enabled = 0; + } if (chan->ops->close != NULL) (*chan->ops->close)(chan->fd, chan->data); diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index 6b7f3827d6e4a..2753718d31b9d 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -21,6 +21,8 @@ #include +extern void free_irqs(void); + /* When epoll triggers we do not know why it did so * we can also have different IRQs for read and write. * This is why we keep a small irq_fd array for each fd - @@ -100,6 +102,8 @@ void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) } } } + + free_irqs(); } static int assign_epoll_events_to_irq(struct irq_entry *irq_entry) -- 2.20.1