diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-09-21 08:46:26 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-10-01 16:29:06 +0100 |
| commit | 25563b581ba3a1f263a00e8c9a97f5e7363be6fd (patch) | |
| tree | b3564a6168f019dd55288ea76dc481d2b2c04832 | |
| parent | c15cd642d437c9f64d397c14ce734e0554d3977b (diff) | |
net: fix possible store tearing in neigh_periodic_work()
While looking at a related syzbot report involving neigh_periodic_work(),
I found that I forgot to add an annotation when deleting an
RCU protected item from a list.
Readers use rcu_deference(*np), we need to use either
rcu_assign_pointer() or WRITE_ONCE() on writer side
to prevent store tearing.
I use rcu_assign_pointer() to have lockdep support,
this was the choice made in neigh_flush_dev().
Fixes: 767e97e1e0db ("neigh: RCU conversion of struct neighbour")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/neighbour.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 6b76cd103195..7212c7e521ef 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -988,7 +988,9 @@ static void neigh_periodic_work(struct work_struct *work) (state == NUD_FAILED || !time_in_range_open(jiffies, n->used, n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) { - *np = n->next; + rcu_assign_pointer(*np, + rcu_dereference_protected(n->next, + lockdep_is_held(&tbl->lock))); neigh_mark_dead(n); write_unlock(&n->lock); neigh_cleanup_and_release(n); |