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 E7D3FCCA495 for ; Tue, 7 Jun 2022 18:58:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352423AbiFGS6F (ORCPT ); Tue, 7 Jun 2022 14:58:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351554AbiFGSUI (ORCPT ); Tue, 7 Jun 2022 14:20:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7285819B1; Tue, 7 Jun 2022 10:53:43 -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 dfw.source.kernel.org (Postfix) with ESMTPS id D7453616A3; Tue, 7 Jun 2022 17:53:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F8D0C36AFE; Tue, 7 Jun 2022 17:53:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624422; bh=FU9f0Sd5qgSs1RHVfcZvJuLbjW3ssxroWVzMd3IWU2c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iuhd6+hDcmOXfgZocB4NKKmns+d9FDDmhPZFHBT+hMr+sL6bUL52fIdCv4rchfu2h o421boahDETlud3OXYoIp15HHRiPb/BSfi2+jdonvbs7K59K51qCa9vuSVJpFmkVOP UdpF7yj7/bGlduG8hLhioED5+8Pn9LBIODmshPczwdTzdVi4oCEVhGDQCSnQfVdAm7 Y/N1X6qRkL8fYX1U9/52PPzAwa2+F74OYBXYITQFWKmvJZClW21+DuR5X4kI25wwdN waxzOJ0DHoUbQD6cd9YiRq3cXHDFBDUz2e5fYDV7sqJkAqQrnrR0eGuapy++E3wRfz Xewct5mfcbuRQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Duoming Zhou , Greg Kroah-Hartman , Sasha Levin , mailhol.vincent@wanadoo.fr, cai.huoqing@linux.dev, chi.minghao@zte.com.cn, linux-usb@vger.kernel.org Subject: [PATCH AUTOSEL 5.17 14/60] drivers: usb: host: Fix deadlock in oxu_bus_suspend() Date: Tue, 7 Jun 2022 13:52:11 -0400 Message-Id: <20220607175259.478835-14-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607175259.478835-1-sashal@kernel.org> References: <20220607175259.478835-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 e82ff2a49672..4f5498521e1b 100644 --- a/drivers/usb/host/oxu210hp-hcd.c +++ b/drivers/usb/host/oxu210hp-hcd.c @@ -3909,8 +3909,10 @@ 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