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Message-ID: <20250326173634.31096-1-atenart@kernel.org>
Date: Wed, 26 Mar 2025 18:36:32 +0100
From: Antoine Tenart <atenart@...nel.org>
To: davem@...emloft.net,
kuba@...nel.org,
pabeni@...hat.com,
edumazet@...gle.com
Cc: Antoine Tenart <atenart@...nel.org>,
netdev@...r.kernel.org
Subject: [PATCH net] net: decrease cached dst counters in dst_release
Upstream fix ac888d58869b ("net: do not delay dst_entries_add() in
dst_release()") moved decrementing the dst count from dst_destroy to
dst_release to avoid accessing already freed data in case of netns
dismantle. However in case CONFIG_DST_CACHE is enabled and OvS+tunnels
are used, this fix is incomplete as the same issue will be seen for
cached dsts:
Unable to handle kernel paging request at virtual address ffff5aabf6b5c000
Call trace:
percpu_counter_add_batch+0x3c/0x160 (P)
dst_release+0xec/0x108
dst_cache_destroy+0x68/0xd8
dst_destroy+0x13c/0x168
dst_destroy_rcu+0x1c/0xb0
rcu_do_batch+0x18c/0x7d0
rcu_core+0x174/0x378
rcu_core_si+0x18/0x30
Fix this by invalidating the cache, and thus decrementing cached dst
counters, in dst_release too.
Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
Signed-off-by: Antoine Tenart <atenart@...nel.org>
---
net/core/dst.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/net/core/dst.c b/net/core/dst.c
index 9552a90d4772..6d76b799ce64 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -165,6 +165,14 @@ static void dst_count_dec(struct dst_entry *dst)
void dst_release(struct dst_entry *dst)
{
if (dst && rcuref_put(&dst->__rcuref)) {
+#ifdef CONFIG_DST_CACHE
+ if (dst->flags & DST_METADATA) {
+ struct metadata_dst *md_dst = (struct metadata_dst *)dst;
+
+ if (md_dst->type == METADATA_IP_TUNNEL)
+ dst_cache_reset_now(&md_dst->u.tun_info.dst_cache);
+ }
+#endif
dst_count_dec(dst);
call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu);
}
--
2.49.0
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