diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-07-25 14:07:24 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-15 12:13:48 +0200 |
| commit | db65739d406c72776fbdbbc334be827ef05880d2 (patch) | |
| tree | b0a9d64d89155eb8bc3e5d7c6f17a4fb373ec5c4 | |
| parent | cd8d8bbd9ced4cc5d06d858f67d4aa87745e8f38 (diff) | |
ipv6: fix possible infinite loop in fib6_info_uses_dev()
[ Upstream commit f8d8ce1b515a0a6af72b30502670a406cfb75073 ]
fib6_info_uses_dev() seems to rely on RCU without an explicit
protection.
Like the prior fix in rt6_nlmsg_size(),
we need to make sure fib6_del_route() or fib6_add_rt2node()
have not removed the anchor from the list, or we risk an infinite loop.
Fixes: d9ccb18f83ea ("ipv6: Fix soft lockups in fib6_select_path under high next hop churn")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250725140725.3626540-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/ipv6/route.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index f1e64c1cc49b..8b84ed926cd1 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5875,16 +5875,21 @@ static bool fib6_info_uses_dev(const struct fib6_info *f6i, if (f6i->fib6_nh->fib_nh_dev == dev) return true; - if (f6i->fib6_nsiblings) { - struct fib6_info *sibling, *next_sibling; + if (READ_ONCE(f6i->fib6_nsiblings)) { + const struct fib6_info *sibling; - list_for_each_entry_safe(sibling, next_sibling, - &f6i->fib6_siblings, fib6_siblings) { - if (sibling->fib6_nh->fib_nh_dev == dev) + rcu_read_lock(); + list_for_each_entry_rcu(sibling, &f6i->fib6_siblings, + fib6_siblings) { + if (sibling->fib6_nh->fib_nh_dev == dev) { + rcu_read_unlock(); return true; + } + if (!READ_ONCE(f6i->fib6_nsiblings)) + break; } + rcu_read_unlock(); } - return false; } |