From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gofer.mess.org (gofer.mess.org [88.97.38.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8EBA4156C6A; Thu, 10 Jul 2025 19:59:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=88.97.38.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752177544; cv=none; b=TJeqAaX+KzLgIToS2SnLfG/JOWcM2ue+v64zBnBCYINeY2yPIkglRxJySOvZ9qw3KJpOnDtiYPaVsnjvXJ261m5kvHBrtS0wUevpGSYGx9Qrs9YlP4zevJqiNLUcCd1ZjX3CGa/Oyztmwq91Evm566DN/WAWkWTo8afZx/N4pqY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752177544; c=relaxed/simple; bh=hIEHGKqnWBN1npDvYQHi5KSQKkSDsFC0CfAOfVnneHI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jAkllENLkV54HMPImMNt/54FE4ZA0njN4oJyaodcp4bKFOK+MqcVBrWXAUTlPnN+H8bVeI6FkpoCcY+CTxpfPTysj/znj9evmVcQwm40JKBKoWUnmNttAjK492GJd/OzPNmUMta6qw4vBzb8wQK5AMmVbwAOaX2njKVzwEc/6MI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org; spf=pass smtp.mailfrom=mess.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=LEkKR+BV; arc=none smtp.client-ip=88.97.38.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mess.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="LEkKR+BV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1752177534; bh=hIEHGKqnWBN1npDvYQHi5KSQKkSDsFC0CfAOfVnneHI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LEkKR+BVcQ2ou0NSHtMKzGA7zc72lp6IcpQlfdwVvbjilOaRYpqw6aHdhWbJd8Ck3 QLZ3ZQ2AWmvFVWaw5Gvv324JKokzMo/HJs+fn4TcC1G9hi4ttzL91Kbus9U9WOPJJn p3GBeH4EJKLtqkRjRKROxCGAJ37o8t5r9Pef4NTXO8UXu5Vn5Jj6za1uUP65eK4to9 8JwtVDC9+lQla5Mu2oTGuQRNW5Oivg1phE+xfXgC3SkYLQV+yG/uGGIoP6IeMzY5bK 3ndSjajjotoPQJNOxlr+vUm69Kd/jWC7FF0TBCE0Y7DnfVsCiy25fUqTKjxd/1xzpH FN1yAVJMyUxtQ== Received: by gofer.mess.org (Postfix, from userid 1000) id DB06F1002BF; Thu, 10 Jul 2025 20:58:54 +0100 (BST) Date: Thu, 10 Jul 2025 20:58:54 +0100 From: Sean Young To: Tetsuo Handa Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, LKML Subject: Re: [PATCH] media: imon: ratelimit usb_rx_callback_intf{0,1} error messages Message-ID: References: <56c16d80-57d0-4873-98c8-03e37edbbbdf@I-love.SAKURA.ne.jp> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56c16d80-57d0-4873-98c8-03e37edbbbdf@I-love.SAKURA.ne.jp> Hello Tetsuo, Thank you for submitting your patch. On Thu, Jul 10, 2025 at 10:43:56AM +0900, Tetsuo Handa wrote: > Ratelimiting flood of > > imon 1-1:0.0: imon usb_rx_callback_intf0: status(-71): ignored > > message helps reducing possibility of hitting > > rcu: INFO: rcu_preempt self-detected stall on CPU > rcu: 0-....: (10485 ticks this GP) idle=ff54/1/0x4000000000000000 softirq=53201/53201 fqs=5246 > rcu: hardirqs softirqs csw/system > rcu: number: 6548 7856 0 > rcu: cputime: 0 739 51598 ==> 52490(ms) > rcu: (t=10500 jiffies g=34137 q=35661 ncpus=2) > CPU: 0 UID: 0 PID: 6858 Comm: kworker/0:4 Not tainted 6.16.0-rc4-syzkaller-00300-g81c3b7256f9e #0 PREEMPT(voluntary) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 > Workqueue: usb_hub_wq hub_event > RIP: 0010:console_flush_all+0x9a2/0xc60 kernel/printk/printk.c:3227 > > messages. > > Link: https://syzkaller.appspot.com/bug?extid=592e2ab8775dbe0bf09a > Signed-off-by: Tetsuo Handa > --- > drivers/media/rc/imon.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c > index f5221b018808..10124a26ffde 100644 > --- a/drivers/media/rc/imon.c > +++ b/drivers/media/rc/imon.c > @@ -1765,7 +1765,7 @@ static void usb_rx_callback_intf0(struct urb *urb) > break; > > default: > - dev_warn(ictx->dev, "imon %s: status(%d): ignored\n", > + dev_warn_ratelimited(ictx->dev, "imon %s: status(%d): ignored\n", > __func__, urb->status); I'm not sure this is the right way to go about this. When the usb callback receives urb status -71 (-EPROTO, i.e. protocol error or unplug), then there is no use in continuing to resubmit the urb; you will only get more failures like you are seeing here. So I think for -EPROTO, simply return and do not resubmit the urb. TBH I am not sure if usb_unlink_urb() is required in this case, that needs investigation. > break; > } > @@ -1806,7 +1806,7 @@ static void usb_rx_callback_intf1(struct urb *urb) > break; > > default: > - dev_warn(ictx->dev, "imon %s: status(%d): ignored\n", > + dev_warn_ratelimited(ictx->dev, "imon %s: status(%d): ignored\n", > __func__, urb->status); Same here. > break; > } > -- > 2.47.1 >