From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (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 DA1906D17 for ; Wed, 18 Aug 2021 23:42:49 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10080"; a="213329551" X-IronPort-AV: E=Sophos;i="5.84,333,1620716400"; d="scan'208";a="213329551" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Aug 2021 16:42:47 -0700 X-IronPort-AV: E=Sophos;i="5.84,333,1620716400"; d="scan'208";a="449944707" Received: from mjmartin-desk2.amr.corp.intel.com (HELO mjmartin-desk2.intel.com) ([10.209.117.66]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Aug 2021 16:42:47 -0700 From: Mat Martineau To: netdev@vger.kernel.org Cc: Paolo Abeni , davem@davemloft.net, kuba@kernel.org, matthieu.baerts@tessares.net, mptcp@lists.linux.dev, geliangtang@gmail.com, Mat Martineau Subject: [PATCH net 1/2] mptcp: fix memory leak on address flush Date: Wed, 18 Aug 2021 16:42:36 -0700 Message-Id: <20210818234237.242266-2-mathew.j.martineau@linux.intel.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210818234237.242266-1-mathew.j.martineau@linux.intel.com> References: <20210818234237.242266-1-mathew.j.martineau@linux.intel.com> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Paolo Abeni The endpoint cleanup path is prone to a memory leak, as reported by syzkaller: BUG: memory leak unreferenced object 0xffff88810680ea00 (size 64): comm "syz-executor.6", pid 6191, jiffies 4295756280 (age 24.138s) hex dump (first 32 bytes): 58 75 7d 3c 80 88 ff ff 22 01 00 00 00 00 ad de Xu}<...."....... 01 00 02 00 00 00 00 00 ac 1e 00 07 00 00 00 00 ................ backtrace: [<0000000072a9f72a>] kmalloc include/linux/slab.h:591 [inline] [<0000000072a9f72a>] mptcp_nl_cmd_add_addr+0x287/0x9f0 net/mptcp/pm_netlink.c:1170 [<00000000f6e931bf>] genl_family_rcv_msg_doit.isra.0+0x225/0x340 net/netlink/genetlink.c:731 [<00000000f1504a2c>] genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] [<00000000f1504a2c>] genl_rcv_msg+0x341/0x5b0 net/netlink/genetlink.c:792 [<0000000097e76f6a>] netlink_rcv_skb+0x148/0x430 net/netlink/af_netlink.c:2504 [<00000000ceefa2b8>] genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 [<000000008ff91aec>] netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] [<000000008ff91aec>] netlink_unicast+0x537/0x750 net/netlink/af_netlink.c:1340 [<0000000041682c35>] netlink_sendmsg+0x846/0xd80 net/netlink/af_netlink.c:1929 [<00000000df3aa8e7>] sock_sendmsg_nosec net/socket.c:704 [inline] [<00000000df3aa8e7>] sock_sendmsg+0x14e/0x190 net/socket.c:724 [<000000002154c54c>] ____sys_sendmsg+0x709/0x870 net/socket.c:2403 [<000000001aab01d7>] ___sys_sendmsg+0xff/0x170 net/socket.c:2457 [<00000000fa3b1446>] __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486 [<00000000db2ee9c7>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<00000000db2ee9c7>] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80 [<000000005873517d>] entry_SYSCALL_64_after_hwframe+0x44/0xae We should not require an allocation to cleanup stuff. Rework the code a bit so that the additional RCU work is no more needed. Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau --- net/mptcp/pm_netlink.c | 44 ++++++++++++------------------------------ 1 file changed, 12 insertions(+), 32 deletions(-) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 56263c2c4014..7b3794459783 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1135,36 +1135,12 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net, return 0; } -struct addr_entry_release_work { - struct rcu_work rwork; - struct mptcp_pm_addr_entry *entry; -}; - -static void mptcp_pm_release_addr_entry(struct work_struct *work) +/* caller must ensure the RCU grace period is already elapsed */ +static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry) { - struct addr_entry_release_work *w; - struct mptcp_pm_addr_entry *entry; - - w = container_of(to_rcu_work(work), struct addr_entry_release_work, rwork); - entry = w->entry; - if (entry) { - if (entry->lsk) - sock_release(entry->lsk); - kfree(entry); - } - kfree(w); -} - -static void mptcp_pm_free_addr_entry(struct mptcp_pm_addr_entry *entry) -{ - struct addr_entry_release_work *w; - - w = kmalloc(sizeof(*w), GFP_ATOMIC); - if (w) { - INIT_RCU_WORK(&w->rwork, mptcp_pm_release_addr_entry); - w->entry = entry; - queue_rcu_work(system_wq, &w->rwork); - } + if (entry->lsk) + sock_release(entry->lsk); + kfree(entry); } static int mptcp_nl_remove_id_zero_address(struct net *net, @@ -1244,7 +1220,8 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info) spin_unlock_bh(&pernet->lock); mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr); - mptcp_pm_free_addr_entry(entry); + synchronize_rcu(); + __mptcp_pm_release_addr_entry(entry); return ret; } @@ -1297,6 +1274,7 @@ static void mptcp_nl_remove_addrs_list(struct net *net, } } +/* caller must ensure the RCU grace period is already elapsed */ static void __flush_addrs(struct list_head *list) { while (!list_empty(list)) { @@ -1305,7 +1283,7 @@ static void __flush_addrs(struct list_head *list) cur = list_entry(list->next, struct mptcp_pm_addr_entry, list); list_del_rcu(&cur->list); - mptcp_pm_free_addr_entry(cur); + __mptcp_pm_release_addr_entry(cur); } } @@ -1329,6 +1307,7 @@ static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info) bitmap_zero(pernet->id_bitmap, MAX_ADDR_ID + 1); spin_unlock_bh(&pernet->lock); mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list); + synchronize_rcu(); __flush_addrs(&free_list); return 0; } @@ -1939,7 +1918,8 @@ static void __net_exit pm_nl_exit_net(struct list_head *net_list) struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id); /* net is removed from namespace list, can't race with - * other modifiers + * other modifiers, also netns core already waited for a + * RCU grace period. */ __flush_addrs(&pernet->local_addr_list); } -- 2.33.0