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Received: from mga04.intel.com ([192.55.52.120]) by casper.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1csmxn-0002Kw-LY for linux-arm-kernel@lists.infradead.org; Tue, 28 Mar 2017 08:58:54 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=intel.com; i=@intel.com; q=dns/txt; s=intel; t=1490691531; x=1522227531; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=wGWVxvxD3ePVK04snav1PQ56XJFktTEUNVUWjFAL9wI=; b=dgvKIx9OEvCU6PlS/8RyY6zbhkdUWstvU7QPJgRF9g8QJXOmJyJbPXdl 7f4mkkZeb4d8PDKtsGj6+q1ednbuog==; Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Mar 2017 01:58:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,236,1486454400"; d="scan'208";a="81798271" Received: from unknown (HELO elena-ThinkPad-X230.ger.corp.intel.com) ([10.249.44.56]) by fmsmga006.fm.intel.com with ESMTP; 28 Mar 2017 01:58:23 -0700 From: Elena Reshetova To: netdev@vger.kernel.org Subject: [PATCH 14/16] drivers, net, ppp: convert syncppp.refcnt from atomic_t to refcount_t Date: Tue, 28 Mar 2017 11:56:41 +0300 Message-Id: <1490691403-4016-15-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1490691403-4016-1-git-send-email-elena.reshetova@intel.com> References: <1490691403-4016-1-git-send-email-elena.reshetova@intel.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170328_095852_030033_0BA10F49 X-CRM114-Status: GOOD ( 14.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peterz@infradead.org, matanb@mellanox.com, paulus@samba.org, Elena Reshetova , nbd@openwrt.org, linux-rdma@vger.kernel.org, saeedm@mellanox.com, ganeshgr@chelsio.com, Hans Liljestrand , David Windsor , keescook@chromium.org, j@w1.fi, ajk@comnets.uni-bremen.de, leonro@mellanox.com, matthias.bgg@gmail.com, linux-hams@vger.kernel.org, kvalo@codeaurora.org, blogic@openwrt.org, linux-arm-kernel@lists.infradead.org, linux-ppp@vger.kernel.org, yishaih@mellanox.com, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- drivers/net/ppp/ppp_synctty.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c index 9ae5398..4a643f8 100644 --- a/drivers/net/ppp/ppp_synctty.c +++ b/drivers/net/ppp/ppp_synctty.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include @@ -72,7 +73,7 @@ struct syncppp { struct tasklet_struct tsk; - atomic_t refcnt; + refcount_t refcnt; struct completion dead_cmp; struct ppp_channel chan; /* interface to generic ppp layer */ }; @@ -141,14 +142,14 @@ static struct syncppp *sp_get(struct tty_struct *tty) read_lock(&disc_data_lock); ap = tty->disc_data; if (ap != NULL) - atomic_inc(&ap->refcnt); + refcount_inc(&ap->refcnt); read_unlock(&disc_data_lock); return ap; } static void sp_put(struct syncppp *ap) { - if (atomic_dec_and_test(&ap->refcnt)) + if (refcount_dec_and_test(&ap->refcnt)) complete(&ap->dead_cmp); } @@ -182,7 +183,7 @@ ppp_sync_open(struct tty_struct *tty) skb_queue_head_init(&ap->rqueue); tasklet_init(&ap->tsk, ppp_sync_process, (unsigned long) ap); - atomic_set(&ap->refcnt, 1); + refcount_set(&ap->refcnt, 1); init_completion(&ap->dead_cmp); ap->chan.private = ap; @@ -232,7 +233,7 @@ ppp_sync_close(struct tty_struct *tty) * our channel ops (i.e. ppp_sync_send/ioctl) are in progress * by the time it returns. */ - if (!atomic_dec_and_test(&ap->refcnt)) + if (!refcount_dec_and_test(&ap->refcnt)) wait_for_completion(&ap->dead_cmp); tasklet_kill(&ap->tsk);