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 90935CCA483 for ; Thu, 21 Jul 2022 01:58:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231438AbiGUB6R (ORCPT ); Wed, 20 Jul 2022 21:58:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229934AbiGUB6Q (ORCPT ); Wed, 20 Jul 2022 21:58:16 -0400 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17F3C6E2D6; Wed, 20 Jul 2022 18:58:16 -0700 (PDT) Received: by mail-pj1-x102b.google.com with SMTP id o5-20020a17090a3d4500b001ef76490983so134781pjf.2; Wed, 20 Jul 2022 18:58:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ftZmQnNxSbBgGxR5gxqXE4IdbtT6X/p5Ec8B9Vn+x7g=; b=qrRsvYIvHunFmKLnL0KKZbsoF09Zae5Nyxvvp2JUqqOcFmHuOoxROb4Y6mPqazxavg rGfHsgv+zn+DUzRYJ4SbH/V2z3b2JKQL9j7fTxh3dYNw1cgM3P5MaCtBBFzaV3SvqqcM pNfoobD89tofIJPydUuJrl5oJDVQ2pBV8TpDI3lHn6paymKtf1UxTHC4EgwMY/fmh4iI Im5gckNJ/CB1WldghugzlBjcs1wZRPQH6d73De7jcFjsmIWIpq56LOYdaa4N7cZMs2+R fEQXwhvMuf3m4rwTLSkBVeQhLxkSGDL+e+xt3BCoyjvokTPaRnI7ILbaYaAFF6EeV/gk 06JA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ftZmQnNxSbBgGxR5gxqXE4IdbtT6X/p5Ec8B9Vn+x7g=; b=bgPqM32J6aAQ+p27skfNSn6NHm9QUHhjHZUown9xabM3yGfSq7qVhzd9SvmJBWzixC 14MP9CukMSeymDi3EWiv2EP1DraV3Kv5/WOxoagwioW+yypyTg2ABGdmkgh9/uUrGdrD gYPnXUPr5MMCekz1uLJqRerYvwWmY1XUvRh59GfOg7tVw6J0mjWRFsb89A/p+RRpI06i 137H26k600L0n7763paPvnxSn6zdSPRHNRqpycWEKv56UBHhYfnShywCJf4FTmV0G15V Rd9Tssjnk3meCD/C2PF01iXv4oI5nXVNCmAEIJlTeI9s3y/EGQ0YSw4qBWz0Yi6ry6ER L/kw== X-Gm-Message-State: AJIora9NZvHVunUigUogkWPqYDaKhybJ6konO0cPQvi1Og+uXjck715P 9YhEE4aIhSwrO2Kc1vqOQmkmo6Ltjpot9b6en68= X-Google-Smtp-Source: AGRyM1t6N7pQcjCsI7OAPPR2xzUGupyIxto7KPa5rosYau5ExUl6th5F/uXzTmwuWKLkGf+X0VhV2mO9Jk/JkPR4BUk= X-Received: by 2002:a17:90a:b785:b0:1f1:be59:a607 with SMTP id m5-20020a17090ab78500b001f1be59a607mr8540324pjr.84.1658368695502; Wed, 20 Jul 2022 18:58:15 -0700 (PDT) MIME-Version: 1.0 References: <20220715072951.859586-1-dario.binacchi@amarulasolutions.com> In-Reply-To: <20220715072951.859586-1-dario.binacchi@amarulasolutions.com> From: Souptick Joarder Date: Thu, 21 Jul 2022 07:28:03 +0530 Message-ID: Subject: Re: [PATCH v3] can: slcan: do not sleep with a spin lock held To: Dario Binacchi Cc: linux-kernel@vger.kernel.org, ltp@lists.linux.it, Jeroen Hofstee , kbuild test robot , Richard Palethorpe , kernel test robot , lkp@lists.01.org, Jiri Slaby , Linux Memory Management List , "David S. Miller" , Eric Dumazet , Greg Kroah-Hartman , Jakub Kicinski , Marc Kleine-Budde , Paolo Abeni , Sebastian Andrzej Siewior , Vincent Mailhol , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jul 15, 2022 at 1:00 PM Dario Binacchi wrote: > > We can't call close_candev() with a spin lock held, so release the lock > before calling it. After calling close_candev(), we can update the > fields of the private `struct can_priv' without having to acquire the > lock. But here we are updating private 'struct can_priv' before close_candev() while taking the lock. If we go by change logs, then spin_unlock_bh() need to called before close_candev() and we can update the private 'struct can_priv' in existing place. > > Fixes: c4e54b063f42f ("can: slcan: use CAN network device driver API") > Reported-by: kernel test robot > Link: https://lore.kernel.org/linux-kernel/Ysrf1Yc5DaRGN1WE@xsang-OptiPlex-9020/ > Signed-off-by: Dario Binacchi > > --- > > Changes in v3: > - Update the commit message. > - Reset sl->rcount and sl->xleft before releasing the spin lock. > > Changes in v2: > - Release the lock just before calling the close_candev(). > > drivers/net/can/slcan/slcan-core.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c > index 54d29a410ad5..d40ddc596596 100644 > --- a/drivers/net/can/slcan/slcan-core.c > +++ b/drivers/net/can/slcan/slcan-core.c > @@ -689,15 +689,14 @@ static int slc_close(struct net_device *dev) > clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); > } > netif_stop_queue(dev); > + sl->rcount = 0; > + sl->xleft = 0; > + spin_unlock_bh(&sl->lock); > close_candev(dev); > sl->can.state = CAN_STATE_STOPPED; > if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN) > sl->can.bittiming.bitrate = CAN_BITRATE_UNSET; > > - sl->rcount = 0; > - sl->xleft = 0; > - spin_unlock_bh(&sl->lock); > - > return 0; > } > > -- > 2.32.0 > >