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 DDF98CCA47B for ; Mon, 13 Jun 2022 12:45:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239981AbiFMMpz (ORCPT ); Mon, 13 Jun 2022 08:45:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353571AbiFMMnC (ORCPT ); Mon, 13 Jun 2022 08:43:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F2AB606FC; Mon, 13 Jun 2022 04:10:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 83FCCB80EA7; Mon, 13 Jun 2022 11:10:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D240FC34114; Mon, 13 Jun 2022 11:10:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655118643; bh=u7IYr3xHt6zjUsYbe5rv2BB9TYgoCtrosryJQ3AJNdM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UljzC4nnvcKQiA2zae5of9RsDs0jhPfbVlF2Pd/Eb3dTC5n/hXiKqdHJMEwxadU8W wqosK0NuecadcIUo5ono6wLiLa+7sh7STRZGC5zNTjzl/oxW1C9259nJ++RTk0ohow DD9CNmxhfCaKDtdKSFQ4dpFE928d8Fik4ZD/DYJo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Duoming Zhou , Sasha Levin Subject: [PATCH 5.10 123/172] drivers: usb: host: Fix deadlock in oxu_bus_suspend() Date: Mon, 13 Jun 2022 12:11:23 +0200 Message-Id: <20220613094920.063959333@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094850.166931805@linuxfoundation.org> References: <20220613094850.166931805@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Duoming Zhou [ Upstream commit 4d378f2ae58138d4c55684e1d274e7dd94aa6524 ] There is a deadlock in oxu_bus_suspend(), which is shown below: (Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) ... | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | ... We hold oxu->lock in position (1) of thread 1, and use del_timer_sync() to wait timer to stop, but timer handler also need oxu->lock in position (2) of thread 2. As a result, oxu_bus_suspend() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irq(), which could let timer handler to obtain the needed lock. Signed-off-by: Duoming Zhou Link: https://lore.kernel.org/r/20220417120305.64577-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/host/oxu210hp-hcd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/host/oxu210hp-hcd.c b/drivers/usb/host/oxu210hp-hcd.c index e832909a924f..6df2881cd7b9 100644 --- a/drivers/usb/host/oxu210hp-hcd.c +++ b/drivers/usb/host/oxu210hp-hcd.c @@ -3908,8 +3908,10 @@ static int oxu_bus_suspend(struct usb_hcd *hcd) } } + spin_unlock_irq(&oxu->lock); /* turn off now-idle HC */ del_timer_sync(&oxu->watchdog); + spin_lock_irq(&oxu->lock); ehci_halt(oxu); hcd->state = HC_STATE_SUSPENDED; -- 2.35.1