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 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
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-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Date: Thu, 8 Mar 2018 13:16:43 +0100
Subject: bpf: fix memory leak in lpm_trie map_free callback function
To: gregkh@xxxxxxxxxxxxxxxxxxx
Cc: ast@xxxxxxxxxx, daniel@xxxxxxxxxxxxx, stable@xxxxxxxxxxxxxxx, Yonghong Song <yhs@xxxxxx>
Message-ID: <92a9bac0950f4c6def7378bc548eeaea6518b4da.1520507630.git.daniel@xxxxxxxxxxxxx>
From: Yonghong Song <yhs@xxxxxx>
[ 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@xxxxxxxxxx>
Reported-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Tested-by: Mathieu Malaterre <malat@xxxxxxxxxx>
Signed-off-by: Yonghong Song <yhs@xxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -560,7 +560,10 @@ 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
@@ -574,7 +577,7 @@ 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];
@@ -592,8 +595,8 @@ 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@xxxxxxxxxxxxx are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch