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| author | Eric Dumazet <edumazet@google.com> | 2021-12-10 08:44:21 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-12-10 15:38:26 +0100 |
| commit | 9ba74e6c9e9d0c5c1e5792a7111fc7d1a0589cb8 (patch) | |
| tree | 0984bfcc460de30d23f22d4230992964496199da /include/net | |
| parent | sh_eth: Use dev_err_probe() helper (diff) | |
| download | linux-9ba74e6c9e9d0c5c1e5792a7111fc7d1a0589cb8.tar.xz linux-9ba74e6c9e9d0c5c1e5792a7111fc7d1a0589cb8.zip | |
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 'include/net')
| -rw-r--r-- | include/net/net_namespace.h | 34 | ||||
| -rw-r--r-- | include/net/net_trackers.h | 18 |
2 files changed, 52 insertions, 0 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index bb5fa5914032..5b61c462e534 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -34,6 +34,7 @@ #include <net/netns/smc.h> #include <net/netns/bpf.h> #include <net/netns/mctp.h> +#include <net/net_trackers.h> #include <linux/ns_common.h> #include <linux/idr.h> #include <linux/skbuff.h> @@ -87,6 +88,7 @@ struct net { struct idr netns_ids; struct ns_common ns; + struct ref_tracker_dir refcnt_tracker; struct list_head dev_base_head; struct proc_dir_entry *proc_net; @@ -240,6 +242,7 @@ void ipx_unregister_sysctl(void); #ifdef CONFIG_NET_NS void __put_net(struct net *net); +/* Try using get_net_track() instead */ static inline struct net *get_net(struct net *net) { refcount_inc(&net->ns.count); @@ -258,6 +261,7 @@ static inline struct net *maybe_get_net(struct net *net) return net; } +/* Try using put_net_track() instead */ static inline void put_net(struct net *net) { if (refcount_dec_and_test(&net->ns.count)) @@ -308,6 +312,36 @@ static inline int check_net(const struct net *net) #endif +static inline void netns_tracker_alloc(struct net *net, + netns_tracker *tracker, gfp_t gfp) +{ +#ifdef CONFIG_NET_NS_REFCNT_TRACKER + ref_tracker_alloc(&net->refcnt_tracker, tracker, gfp); +#endif +} + +static inline void netns_tracker_free(struct net *net, + netns_tracker *tracker) +{ +#ifdef CONFIG_NET_NS_REFCNT_TRACKER + ref_tracker_free(&net->refcnt_tracker, tracker); +#endif +} + +static inline struct net *get_net_track(struct net *net, + netns_tracker *tracker, gfp_t gfp) +{ + get_net(net); + netns_tracker_alloc(net, tracker, gfp); + return net; +} + +static inline void put_net_track(struct net *net, netns_tracker *tracker) +{ + netns_tracker_free(net, tracker); + put_net(net); +} + typedef struct { #ifdef CONFIG_NET_NS struct net *net; diff --git a/include/net/net_trackers.h b/include/net/net_trackers.h new file mode 100644 index 000000000000..d94c76cf15a9 --- /dev/null +++ b/include/net/net_trackers.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NET_NET_TRACKERS_H +#define __NET_NET_TRACKERS_H +#include <linux/ref_tracker.h> + +#ifdef CONFIG_NET_DEV_REFCNT_TRACKER +typedef struct ref_tracker *netdevice_tracker; +#else +typedef struct {} netdevice_tracker; +#endif + +#ifdef CONFIG_NET_NS_REFCNT_TRACKER +typedef struct ref_tracker *netns_tracker; +#else +typedef struct {} netns_tracker; +#endif + +#endif /* __NET_NET_TRACKERS_H */ |