From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vps0.lunn.ch (vps0.lunn.ch [156.67.10.101]) (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 869C0219301; Sat, 20 Sep 2025 15:31:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=156.67.10.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758382268; cv=none; b=UEY57LssJgkBXpSkRGJQI/ve3wdUqzBsW9KUVlB+pCO5+BRQLr7EHziqIMg2vQKVyI7S9sTgN9SNHYY/cBumQqwBgYwoIdYHjK4NxDjfRFpJ2KLTCM21LHqABSPYXcER1KxBkujjE+hvInH9Ojcpmksw5emAlg8YK8fqn2JVVyc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758382268; c=relaxed/simple; bh=VmpXs+T5FJFMh9uMlfY1zO0F1J8+Bi53OUp0N4Q+6Y8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RC8dO5PrXiQrx0U5tEQxQWHV0Gp0MacnnD7iEEgpociJ52IjpFa+sFhhHcBAhs9/v1bbEOyOeTlzdwCwLqf1ycCDa4WcV32R0ueGCgtYypPcE5i5a7WbltTD2fSC7mo0o4jyeLoVc3fcG/+AbtlS4HjyjXk5wNp9TnuZpWCscZY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch; spf=pass smtp.mailfrom=lunn.ch; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b=oeHi3YvS; arc=none smtp.client-ip=156.67.10.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lunn.ch Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="oeHi3YvS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=l3P7xbNm51dRG4YbNP1VYdE4uOUg89upg8bJchvamQY=; b=oeHi3YvSJt50OQWpfvMD3AnU28 IBiODy924lqyKQsQ74HLH6chjOVrcyJIGZ7Lj2lk9xcLEQFW5wk2WqNdrJwWHW4+boq8lmbuUqACa 4qqSk1nGV8gMO/iuq9+R7fvIpBslDj0JnT26ZrOQP3V1OaUHpgcsDt/PtQQoicW5+YWY=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1uzzXo-0091G0-9s; Sat, 20 Sep 2025 17:30:36 +0200 Date: Sat, 20 Sep 2025 17:30:36 +0200 From: Andrew Lunn To: I Viswanath Cc: petkan@nucleusys.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux-usb@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linux.dev, david.hunter.linux@gmail.com, syzbot+78cae3f37c62ad092caa@syzkaller.appspotmail.com Subject: Re: [PATCH] net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast Message-ID: <5b51d80e-e67c-437d-a2fc-bebdf5e9a958@lunn.ch> References: <20250920045059.48400-1-viswanathiyyappan@gmail.com> Precedence: bulk X-Mailing-List: netdev@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: <20250920045059.48400-1-viswanathiyyappan@gmail.com> On Sat, Sep 20, 2025 at 10:20:59AM +0530, I Viswanath wrote: > syzbot reported WARNING in rtl8150_start_xmit/usb_submit_urb. > This is a possible sequence of events: > > CPU0 (in rtl8150_start_xmit) CPU1 (in rtl8150_start_xmit) CPU2 (in rtl8150_set_multicast) > netif_stop_queue(); > netif_stop_queue(); > usb_submit_urb(); > netif_wake_queue(); <-- Wakes up TX queue before it's ready > netif_stop_queue(); > usb_submit_urb(); <-- Warning > freeing urb > > Remove netif_wake_queue and corresponding netif_stop_queue in rtl8150_set_multicast to > prevent this sequence of events Please expand this sentence with an explanation of why this is safe. Why are these two calls not needed? The original author of this code thought they where needed, so you need to explain why they are not needed. Andrew --- pw-bot: cr