From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net V2] tuntap: correctly wake up process during uninit Date: Fri, 20 May 2016 19:38:06 -0400 (EDT) Message-ID: <20160520.193806.543505636945844730.davem@davemloft.net> References: <1463636211-3573-1-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, edumazet@google.com, xii@google.com, mst@redhat.com To: jasowang@redhat.com Return-path: In-Reply-To: <1463636211-3573-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Jason Wang Date: Thu, 19 May 2016 13:36:51 +0800 > We used to check dev->reg_state against NETREG_REGISTERED after each > time we are woke up. But after commit 9e641bdcfa4e ("net-tun: > restructure tun_do_read for better sleep/wakeup efficiency"), it uses > skb_recv_datagram() which does not check dev->reg_state. This will > result if we delete a tun/tap device after a process is blocked in the > reading. The device will wait for the reference count which was held > by that process for ever. > > Fixes this by using RCV_SHUTDOWN which will be checked during > sk_recv_datagram() before trying to wake up the process during uninit. > > Fixes: 9e641bdcfa4e ("net-tun: restructure tun_do_read for better > sleep/wakeup efficiency") > Cc: Eric Dumazet > Cc: Xi Wang > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > - The patch is needed for -stable. > - Changes from v1: remove unnecessary NETREG_REGISTERED check in tun_do_read() Applied and queued up for -stable.