diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2015-09-16 00:30:07 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-09-16 00:53:05 +0300 |
| commit | cdf3464e6c6bd764277cbbe992cd12da735b92fb (patch) | |
| tree | 53e75a7f94aba7ced57ae7f2b527bce0d463a629 /include/net | |
| parent | f230d1e891ba1da5953460516960894154f265db (diff) | |
| download | linux-cdf3464e6c6bd764277cbbe992cd12da735b92fb.tar.xz | |
ipv6: Fix dst_entry refcnt bugs in ip6_tunnel
Problems in the current dst_entry cache in the ip6_tunnel:
1. ip6_tnl_dst_set is racy. There is no lock to protect it:
- One major problem is that the dst refcnt gets messed up. F.e.
the same dst_cache can be released multiple times and then
triggering the infamous dst refcnt < 0 warning message.
- Another issue is the inconsistency between dst_cache and
dst_cookie.
It can be reproduced by adding and removing the ip6gre tunnel
while running a super_netperf TCP_CRR test.
2. ip6_tnl_dst_get does not take the dst refcnt before returning
the dst.
This patch:
1. Create a percpu dst_entry cache in ip6_tnl
2. Use a spinlock to protect the dst_cache operations
3. ip6_tnl_dst_get always takes the dst refcnt before returning
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/ip6_tunnel.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h index 979b081a47e8..60b4f402f78c 100644 --- a/include/net/ip6_tunnel.h +++ b/include/net/ip6_tunnel.h @@ -32,6 +32,12 @@ struct __ip6_tnl_parm { __be32 o_key; }; +struct ip6_tnl_dst { + spinlock_t lock; + struct dst_entry *dst; + u32 cookie; +}; + /* IPv6 tunnel */ struct ip6_tnl { struct ip6_tnl __rcu *next; /* next tunnel in list */ @@ -39,8 +45,7 @@ struct ip6_tnl { struct net *net; /* netns for packet i/o */ struct __ip6_tnl_parm parms; /* tunnel configuration parameters */ struct flowi fl; /* flowi template for xmit */ - struct dst_entry *dst_cache; /* cached dst */ - u32 dst_cookie; + struct ip6_tnl_dst __percpu *dst_cache; /* cached dst */ int err_count; unsigned long err_time; @@ -61,6 +66,8 @@ struct ipv6_tlv_tnl_enc_lim { } __packed; struct dst_entry *ip6_tnl_dst_get(struct ip6_tnl *t); +int ip6_tnl_dst_init(struct ip6_tnl *t); +void ip6_tnl_dst_destroy(struct ip6_tnl *t); void ip6_tnl_dst_reset(struct ip6_tnl *t); void ip6_tnl_dst_set(struct ip6_tnl *t, struct dst_entry *dst); int ip6_tnl_rcv_ctl(struct ip6_tnl *t, const struct in6_addr *laddr, |