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| author | Eric Dumazet <dada1@cosmosbay.com> | 2008-10-29 21:19:58 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-10-29 21:19:58 +0300 |
| commit | 96631ed16c514cf8b28fab991a076985ce378c26 (patch) | |
| tree | 60023b60c6eaf2acdc8fcad258585e4425ebaf91 /include/net/sock.h | |
| parent | f52b5054ec108aaa9e903850d6b62af8ae3fe6ae (diff) | |
| download | linux-96631ed16c514cf8b28fab991a076985ce378c26.tar.xz | |
udp: introduce sk_for_each_rcu_safenext()
Corey Minyard found a race added in commit 271b72c7fa82c2c7a795bc16896149933110672d
(udp: RCU handling for Unicast packets.)
"If the socket is moved from one list to another list in-between the
time the hash is calculated and the next field is accessed, and the
socket has moved to the end of the new list, the traversal will not
complete properly on the list it should have, since the socket will
be on the end of the new list and there's not a way to tell it's on a
new list and restart the list traversal. I think that this can be
solved by pre-fetching the "next" field (with proper barriers) before
checking the hash."
This patch corrects this problem, introducing a new
sk_for_each_rcu_safenext() macro.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/sock.h')
| -rw-r--r-- | include/net/sock.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 0bea25db5471..a4f6d3fc0470 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -419,8 +419,8 @@ static __inline__ void sk_add_bind_node(struct sock *sk, #define sk_for_each(__sk, node, list) \ hlist_for_each_entry(__sk, node, list, sk_node) -#define sk_for_each_rcu(__sk, node, list) \ - hlist_for_each_entry_rcu(__sk, node, list, sk_node) +#define sk_for_each_rcu_safenext(__sk, node, list, next) \ + hlist_for_each_entry_rcu_safenext(__sk, node, list, sk_node, next) #define sk_for_each_from(__sk, node) \ if (__sk && ({ node = &(__sk)->sk_node; 1; })) \ hlist_for_each_entry_from(__sk, node, sk_node) |