From patchwork Sat Aug 21 12:18:09 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 348 Return-Path: Received: from mail.gmx.net (mailout-de.gmx.net [213.165.64.22]) by open-mesh.net (Postfix) with SMTP id CA58E154590 for ; Sat, 21 Aug 2010 14:18:30 +0200 (CEST) Received: (qmail invoked by alias); 21 Aug 2010 12:18:29 -0000 Received: from unknown (EHLO sven-desktop.lazhur.ath.cx) [89.246.193.20] by mail.gmx.net (mp062) with SMTP; 21 Aug 2010 14:18:29 +0200 X-Authenticated: #15668376 X-Provags-ID: V01U2FsdGVkX19KyDNpuDZKBNL4/YpMCXtR0O+K+igUXSDeP3hj64 JYImLapgghG9am From: Sven Eckelmann To: greg@kroah.com Date: Sat, 21 Aug 2010 14:18:09 +0200 Message-Id: <1282393090-27411-3-git-send-email-sven.eckelmann@gmx.de> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1282393090-27411-1-git-send-email-sven.eckelmann@gmx.de> References: <1282393090-27411-1-git-send-email-sven.eckelmann@gmx.de> X-Y-GMX-Trusted: 0 Cc: b.a.t.m.a.n@lists.open-mesh.net, stable Subject: [B.A.T.M.A.N.] [PATCH 2/3] Staging: batman-adv: Don't use net_dev after dev_put X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Aug 2010 12:18:32 -0000 dev_put allows a device to be freed when all its references are dropped. After that we are not allowed to access that information anymore. Access to the data structure of a net_device must be surrounded a dev_hold and ended using dev_put. batman-adv adds a device to its own management structure in hardif_add_interface and will release it in hardif_remove_interface. Thus it must hold a reference all the time between those functions to prevent any access to the already released net_device structure. Reported-by: Tim Glaremin Signed-off-by: Sven Eckelmann Cc: stable --- drivers/staging/batman-adv/hard-interface.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c index 892166b..d08491e 100644 --- a/drivers/staging/batman-adv/hard-interface.c +++ b/drivers/staging/batman-adv/hard-interface.c @@ -194,8 +194,6 @@ static void hardif_activate_interface(struct net_device *net_dev, if (batman_if->if_status != IF_INACTIVE) return; - dev_hold(batman_if->net_dev); - update_mac_addresses(batman_if); batman_if->if_status = IF_TO_BE_ACTIVATED; @@ -222,8 +220,6 @@ static void hardif_deactivate_interface(struct net_device *net_dev, (batman_if->if_status != IF_TO_BE_ACTIVATED)) return; - dev_put(batman_if->net_dev); - batman_if->if_status = IF_INACTIVE; bat_info(net_dev, "Interface deactivated: %s\n", batman_if->dev); @@ -318,11 +314,13 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev) if (ret != 1) goto out; + dev_hold(net_dev); + batman_if = kmalloc(sizeof(struct batman_if), GFP_ATOMIC); if (!batman_if) { pr_err("Can't add interface (%s): out of memory\n", net_dev->name); - goto out; + goto release_dev; } batman_if->dev = kstrdup(net_dev->name, GFP_ATOMIC); @@ -346,6 +344,8 @@ free_dev: kfree(batman_if->dev); free_if: kfree(batman_if); +release_dev: + dev_put(net_dev); out: return NULL; } @@ -374,6 +374,7 @@ static void hardif_remove_interface(struct batman_if *batman_if) batman_if->if_status = IF_TO_BE_REMOVED; list_del_rcu(&batman_if->list); sysfs_del_hardif(&batman_if->hardif_obj); + dev_put(batman_if->net_dev); call_rcu(&batman_if->rcu, hardif_free_interface); }