This is a note to let you know that I've just added the patch titled
bpf: fix memory leak in lpm_trie map_free callback function
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Fri Mar 9 14:18:36 PST 2018
From: Daniel Borkmann daniel@iogearbox.net Date: Thu, 8 Mar 2018 13:14:41 +0100 Subject: bpf: fix memory leak in lpm_trie map_free callback function To: gregkh@linuxfoundation.org Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Yonghong Song yhs@fb.com Message-ID: 2cc89f1f07f3d56d271d8734057144e879dc558d.1520504748.git.daniel@iogearbox.net
From: Yonghong Song yhs@fb.com
[ 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 malat@debian.org Reported-by: Alexei Starovoitov ast@kernel.org Tested-by: Mathieu Malaterre malat@debian.org Signed-off-by: Yonghong Song yhs@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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)
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.14/bpf-fix-mlock-precharge-on-arraymaps.patch queue-4.14/bpf-x64-implement-retpoline-for-tail-call.patch queue-4.14/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch queue-4.14/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch queue-4.14/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch queue-4.14/bpf-add-schedule-points-in-percpu-arrays-management.patch queue-4.14/bpf-allow-xadd-only-on-aligned-memory.patch queue-4.14/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch