diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-12-09 23:44:21 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-12-10 06:38:26 -0800 |
| commit | 9ba74e6c9e9d0c5c1e5792a7111fc7d1a0589cb8 (patch) | |
| tree | 0984bfcc460de30d23f22d4230992964496199da /net | |
| parent | e5d75fc20b9278d07731f69e327adf16227813a6 (diff) | |
net: add networking namespace refcount tracker
We have 100+ syzbot reports about netns being dismantled too soon,
still unresolved as of today.
We think a missing get_net() or an extra put_net() is the root cause.
In order to find the bug(s), and be able to spot future ones,
this patch adds CONFIG_NET_NS_REFCNT_TRACKER and new helpers
to precisely pair all put_net() with corresponding get_net().
To use these helpers, each data structure owning a refcount
should also use a "netns_tracker" to pair the get and put.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/Kconfig.debug | 9 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 3 |
2 files changed, 12 insertions, 0 deletions
diff --git a/net/Kconfig.debug b/net/Kconfig.debug index fb5c70e01cb3..2f50611df858 100644 --- a/net/Kconfig.debug +++ b/net/Kconfig.debug @@ -8,3 +8,12 @@ config NET_DEV_REFCNT_TRACKER help Enable debugging feature to track device references. This adds memory and cpu costs. + +config NET_NS_REFCNT_TRACKER + bool "Enable networking namespace refcount tracking" + depends on DEBUG_KERNEL && STACKTRACE_SUPPORT + select REF_TRACKER + default n + help + Enable debugging feature to track netns references. + This adds memory and cpu costs. diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 202fa5eacd0f..9b7171c40434 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -311,6 +311,8 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) LIST_HEAD(net_exit_list); refcount_set(&net->ns.count, 1); + ref_tracker_dir_init(&net->refcnt_tracker, 128); + refcount_set(&net->passive, 1); get_random_bytes(&net->hash_mix, sizeof(u32)); preempt_disable(); @@ -635,6 +637,7 @@ static DECLARE_WORK(net_cleanup_work, cleanup_net); void __put_net(struct net *net) { + ref_tracker_dir_exit(&net->refcnt_tracker); /* Cleanup the network namespace in process context */ if (llist_add(&net->cleanup_list, &cleanup_list)) queue_work(netns_wq, &net_cleanup_work); |