Re: [PATCH] gtp: disable BH before calling udp_tunnel_xmit_skb()

patchwork-bot+netdevbpf
2026-04-20T22:00:23Z

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 17 Apr 2026 06:54:08 +0100 you wrote:
> gtp_genl_send_echo_req() runs as a generic netlink doit handler in
> process context with BH not disabled. It calls udp_tunnel_xmit_skb(),
> which eventually invokes iptunnel_xmit() — that uses __this_cpu_inc/dec
> on softnet_data.xmit.recursion to track the tunnel xmit recursion level.
>
> Without local_bh_disable(), the task may migrate between
> dev_xmit_recursion_inc() and dev_xmit_recursion_dec(), breaking the
> per-CPU counter pairing. The result is stale or negative recursion
> levels that can later produce false-positive
> SKB_DROP_REASON_RECURSION_LIMIT drops on either CPU.
>
> [...]

Here is the summary with links:
- gtp: disable BH before calling udp_tunnel_xmit_skb()
https://git.kernel.org/netdev/net/c/5638504a2aa9

You are awesome, thank you!
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