diff options
| author | David Ahern <dsahern@gmail.com> | 2018-04-20 15:38:02 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-21 16:06:14 -0400 |
| commit | a68886a691804d3f6d479ebf6825480fbafb6a00 (patch) | |
| tree | 2240cab921badf927268bcd687b8b2743179e86c /net/ipv6/ip6_fib.c | |
| parent | 5bcaa41b964ba2cda6dde64a126bfb7da1bd88f8 (diff) | |
net/ipv6: Make from in rt6_info rcu protected
When a dst entry is created from a fib entry, the 'from' in rt6_info
is set to the fib entry. The 'from' reference is used most notably for
cookie checking - making sure stale dst entries are updated if the
fib entry is changed.
When a fib entry is deleted, the pcpu routes on it are walked releasing
the fib6_info reference. This is needed for the fib6_info cleanup to
happen and to make sure all device references are released in a timely
manner.
There is a race window when a FIB entry is deleted and the 'from' on the
pcpu route is dropped and the pcpu route hits a cookie check. Handle
this race using rcu on from.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ip6_fib.c')
| -rw-r--r-- | net/ipv6/ip6_fib.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 64ca02b7745f..6421c893466e 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -875,8 +875,12 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i, ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu); pcpu_rt = *ppcpu_rt; if (pcpu_rt) { - fib6_info_release(pcpu_rt->from); - pcpu_rt->from = NULL; + struct fib6_info *from; + + from = rcu_dereference_protected(pcpu_rt->from, + lockdep_is_held(&table->tb6_lock)); + rcu_assign_pointer(pcpu_rt->from, NULL); + fib6_info_release(from); } } } |