From 7b3c572da4bea75b28593aeede0ab6b87a678012 Mon Sep 17 00:00:00 2001 From: Jakub Sitnicki Date: Sun, 7 Jun 2020 22:52:28 +0200 Subject: [PATCH] bpf, sockhash: Fix memory leak when unlinking sockets in sock_hash_free When sockhash gets destroyed while sockets are still linked to it, we will walk the bucket lists and delete the links. However, we are not freeing the list elements after processing them, leaking the memory. The leak can be triggered by close()'ing a sockhash map when it still contains sockets, and observed with kmemleak: unreferenced object 0xffff888116e86f00 (size 64): comm "race_sock_unlin", pid 223, jiffies 4294731063 (age 217.404s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 81 de e8 41 00 00 00 00 c0 69 2f 15 81 88 ff ff ...A.....i/..... backtrace: [<00000000dd089ebb>] sock_hash_update_common+0x4ca/0x760 [<00000000b8219bd5>] sock_hash_update_elem+0x1d2/0x200 [<000000005e2c23de>] __do_sys_bpf+0x2046/0x2990 [<00000000d0084618>] do_syscall_64+0xad/0x9a0 [<000000000d96f263>] entry_SYSCALL_64_after_hwframe+0x49/0xb3 Fix it by freeing the list element when we're done with it. Fixes: eaf66302e456 ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Jakub Sitnicki Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200607205229.2389672-2-jakub@cloudflare.com --- net/core/sock_map.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 00a26cf2cfe92..ea46f07a22d85 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -1031,6 +1031,7 @@ static void sock_hash_free(struct bpf_map *map) sock_map_unref(elem->sk, elem); rcu_read_unlock(); release_sock(elem->sk); + sock_hash_free_elem(htab, elem); } } -- 2.39.5