diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_core.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_core.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 9f530adad10d..4cbda4bd8926 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -83,6 +83,13 @@ void nf_conntrack_lock(spinlock_t *lock) __acquires(lock) spin_lock(lock); while (unlikely(nf_conntrack_locks_all)) { spin_unlock(lock); + + /* + * Order the 'nf_conntrack_locks_all' load vs. the + * spin_unlock_wait() loads below, to ensure + * that 'nf_conntrack_locks_all_lock' is indeed held: + */ + smp_rmb(); /* spin_lock(&nf_conntrack_locks_all_lock) */ spin_unlock_wait(&nf_conntrack_locks_all_lock); spin_lock(lock); } @@ -128,6 +135,14 @@ static void nf_conntrack_all_lock(void) spin_lock(&nf_conntrack_locks_all_lock); nf_conntrack_locks_all = true; + /* + * Order the above store of 'nf_conntrack_locks_all' against + * the spin_unlock_wait() loads below, such that if + * nf_conntrack_lock() observes 'nf_conntrack_locks_all' + * we must observe nf_conntrack_locks[] held: + */ + smp_mb(); /* spin_lock(&nf_conntrack_locks_all_lock) */ + for (i = 0; i < CONNTRACK_LOCKS; i++) { spin_unlock_wait(&nf_conntrack_locks[i]); } @@ -135,7 +150,13 @@ static void nf_conntrack_all_lock(void) static void nf_conntrack_all_unlock(void) { - nf_conntrack_locks_all = false; + /* + * All prior stores must be complete before we clear + * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock() + * might observe the false value but not the entire + * critical section: + */ + smp_store_release(&nf_conntrack_locks_all, false); spin_unlock(&nf_conntrack_locks_all_lock); } |