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 16:38:55 +0200 |
| commit | e09be457b71b983a085312ff9e981f51e4ed3211 (patch) | |
| tree | f54c99655ae5fb1fa92f1b26ecb490f6a80381c8 | |
| parent | 46aeb66e9e54ed0d56c18615e1c3dbd502b327ab (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 2aeca451aab3..bf71c8ce002f 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5958,16 +5958,21 @@ 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; } |