Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40406 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934064AbeCJAXR (ORCPT ); Fri, 9 Mar 2018 19:23:17 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Yonghong Song" , Mathieu Malaterre , Alexei Starovoitov , Daniel Borkmann , Yonghong Song Subject: [PATCH 4.14 2/9] bpf: fix memory leak in lpm_trie map_free callback function Date: Fri, 9 Mar 2018 16:19:07 -0800 Message-Id: <20180310001828.656537139@linuxfoundation.org> In-Reply-To: <20180310001828.476933393@linuxfoundation.org> References: <20180310001828.476933393@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yonghong Song [ upstream commit 9a3efb6b661f71d5675369ace9257833f0e78ef3 ] There is a memory leak happening in lpm_trie map_free callback function trie_free. The trie structure itself does not get freed. Also, trie_free function did not do synchronize_rcu before freeing various data structures. This is incorrect as some rcu_read_lock region(s) for lookup, update, delete or get_next_key may not complete yet. The fix is to add synchronize_rcu in the beginning of trie_free. The useless spin_lock is removed from this function as well. Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation") Reported-by: Mathieu Malaterre Reported-by: Alexei Starovoitov Tested-by: Mathieu Malaterre Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/lpm_trie.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -470,7 +470,10 @@ static void trie_free(struct bpf_map *ma struct lpm_trie_node __rcu **slot; struct lpm_trie_node *node; - raw_spin_lock(&trie->lock); + /* Wait for outstanding programs to complete + * update/lookup/delete/get_next_key and free the trie. + */ + synchronize_rcu(); /* Always start at the root and walk down to a node that has no * children. Then free that node, nullify its reference in the parent @@ -484,7 +487,7 @@ static void trie_free(struct bpf_map *ma node = rcu_dereference_protected(*slot, lockdep_is_held(&trie->lock)); if (!node) - goto unlock; + goto out; if (rcu_access_pointer(node->child[0])) { slot = &node->child[0]; @@ -502,8 +505,8 @@ static void trie_free(struct bpf_map *ma } } -unlock: - raw_spin_unlock(&trie->lock); +out: + kfree(trie); } static int trie_get_next_key(struct bpf_map *map, void *key, void *next_key)