6.6-stable review patch. If anyone has any objections, please let me know.
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From: Antoine Tenart atenart@kernel.org
[ Upstream commit 3a0a3ff6593d670af2451ec363ccb7b18aec0c0a ]
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@kernel.org Link: https://patch.msgid.link/20250326173634.31096-1-atenart@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/dst.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/net/core/dst.c b/net/core/dst.c index 137b8d1c72203..aad197e761cb4 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -167,6 +167,14 @@ 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); }