From: Ido Schimmel <idosch@nvidia.com>
To: Jun Yang <juny24602@gmail.com>
Cc: dsahern@kernel.org, davem@davemloft.net, edumazet@kernel.org,
kuba@kernel.org, pabeni@redhat.com, horms@kernel.org,
kaber@trash.net, netdev@vger.kernel.org,
Jun Yang <junvyyang@tencent.com>,
stable@kernel.org, TencentOS Corvus AI <corvus@tencent.com>
Subject: Re: [PATCH net] ipv6: take tb6_lock across the fib6 dump sernum snapshot
Date: Tue, 13 Oct 2026 15:41:36 +0300 [thread overview]
Message-ID: <20261013124136.GA1010894@shredder> (raw)
In-Reply-To: <20261012083843.60510-1-juny24602@gmail.com>
On Mon, Oct 12, 2026 at 04:38:20PM +0800, Jun Yang wrote:
[...]
> the replace path has no FOR_WALKERS fixup, unlike fib6_del_route()
Why not fix that instead with something like [1]?
[1]
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 9ff761962b45..b9268b5569a8 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -89,6 +89,24 @@ static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
write_unlock_bh(&net->ipv6.fib6_walker_lock);
}
+static void fib6_adjust_walkers(struct net *net, struct fib6_table *table,
+ struct fib6_info *rt)
+{
+ struct fib6_walker *w;
+
+ read_lock(&net->ipv6.fib6_walker_lock);
+ FOR_WALKERS(net, w) {
+ if (w->state == FWS_C && w->leaf == rt) {
+ pr_debug("walker %p adjusted\n", w);
+ w->leaf = rcu_dereference_protected(rt->fib6_next,
+ lockdep_is_held(&table->tb6_lock));
+ if (!w->leaf)
+ w->state = FWS_U;
+ }
+ }
+ read_unlock(&net->ipv6.fib6_walker_lock);
+}
+
static int fib6_new_sernum(struct net *net)
{
int new, old = atomic_read(&net->ipv6.fib6_sernum);
@@ -1324,6 +1342,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
}
nsiblings = iter->fib6_nsiblings;
iter->fib6_node = NULL;
+ fib6_adjust_walkers(info->nl_net, rt->fib6_table, iter);
list_add(&iter->purge_link, purge_list);
if (rcu_access_pointer(fn->rr_ptr) == iter)
fn->rr_ptr = NULL;
@@ -1339,6 +1358,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
if (rt6_qualify_for_ecmp(iter)) {
*ins = iter->fib6_next;
iter->fib6_node = NULL;
+ fib6_adjust_walkers(info->nl_net, rt->fib6_table, iter);
list_add(&iter->purge_link, purge_list);
if (rcu_access_pointer(fn->rr_ptr) == iter)
fn->rr_ptr = NULL;
@@ -1971,7 +1991,6 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
enum rt_del_reason del_reason)
{
struct fib6_info *leaf, *replace_rt = NULL;
- struct fib6_walker *w;
struct fib6_info *rt = rcu_dereference_protected(*rtp,
lockdep_is_held(&table->tb6_lock));
struct net *net = info->nl_net;
@@ -2022,18 +2041,7 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
rt6_multipath_rebalance(next_sibling);
}
- /* Adjust walkers */
- read_lock(&net->ipv6.fib6_walker_lock);
- FOR_WALKERS(net, w) {
- if (w->state == FWS_C && w->leaf == rt) {
- pr_debug("walker %p adjusted by delroute\n", w);
- w->leaf = rcu_dereference_protected(rt->fib6_next,
- lockdep_is_held(&table->tb6_lock));
- if (!w->leaf)
- w->state = FWS_U;
- }
- }
- read_unlock(&net->ipv6.fib6_walker_lock);
+ fib6_adjust_walkers(net, table, rt);
/* If it was last route, call fib6_repair_tree() to:
* 1. For root node, put back null_entry as how the table was created.
prev parent reply other threads:[~2026-10-13 12:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-12 8:38 [PATCH net] ipv6: take tb6_lock across the fib6 dump sernum snapshot Jun Yang
2026-10-13 8:41 ` netdev-bot+sashiko
2026-10-13 12:41 ` Ido Schimmel [this message]
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