From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [PATCH 2/2] tuntap: fix leaking reference count Date: Fri, 11 Jan 2013 16:50:42 +0800 Message-ID: <1357894242-25020-2-git-send-email-jasowang@redhat.com> References: <1357894242-25020-1-git-send-email-jasowang@redhat.com> Cc: Jason Wang To: davem@davemloft.net, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1357894242-25020-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Reference count leaking of both module and sock were found: - When a detached file were closed, its sock refcnt from device were not released, solving this by add the sock_put(). - The module were hold or drop unconditionally in TUNSETPERSIST, which means we if we set the persist flag for N times, we need unset it for another N times. Solving this by only hold or drop an reference when there's a flag change and also drop the reference count when the persist device is deleted. Signed-off-by: Jason Wang --- drivers/net/tun.c | 12 +++++++++--- 1 files changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9a46d70..d690dc8 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -429,8 +429,10 @@ static void __tun_detach(struct tun_file *tfile, bool clean) /* Drop read queue */ skb_queue_purge(&tfile->sk.sk_receive_queue); tun_set_real_num_queues(tun); - } else if (tfile->detached && clean) + } else if (tfile->detached && clean) { tun = tun_enable_queue(tfile); + sock_put(&tfile->sk); + } if (clean) { if (tun && tun->numqueues == 0 && tun->numdisabled == 0 && @@ -481,6 +483,9 @@ static void tun_detach_all(struct net_device *dev) sock_put(&tfile->sk); } BUG_ON(tun->numdisabled != 0); + + if (tun->flags & TUN_PERSIST) + module_put(THIS_MODULE); } static int tun_attach(struct tun_struct *tun, struct file *file) @@ -1881,10 +1886,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, /* Disable/Enable persist mode. Keep an extra reference to the * module to prevent the module being unprobed. */ - if (arg) { + if (arg && !(tun->flags & TUN_PERSIST)) { tun->flags |= TUN_PERSIST; __module_get(THIS_MODULE); - } else { + } + if (!arg && (tun->flags & TUN_PERSIST)) { tun->flags &= ~TUN_PERSIST; module_put(THIS_MODULE); } -- 1.7.1