Re: [PATCH net v6] net: ipv4: add zero check for snd_cwnd_clamp
From: patchwork-bot+netdevbpf
Date: Tue Oct 27 2026 - 06:51:36 EST
Hello:
This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@xxxxxxxxxx>:
On Wed, 21 Oct 2026 19:57:33 -0400 you wrote:
> When RTAX_CWND is locked, user is able to pass 0 into it.
> This could lead to writing 0 to tp->snd_cwnd, leading to a
> division by zero error.
>
> Oops: divide error: 0000 [#1] SMP KASAN NOPTI
> Call Trace:
> <IRQ>
> tcp_reno_cong_avoid (net/ipv4/tcp_cong.c:510 (discriminator 1))
> tcp_ack (net/ipv4/tcp_input.c:3517 net/ipv4/tcp_input.c:3873 net/ipv4/tcp_input.c:4440)
> tcp_rcv_established (net/ipv4/tcp_input.c:6685)
> tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1854)
> tcp_v4_rcv (net/ipv4/tcp_ipv4.c:2248)
> ip_protocol_deliver_rcu (net/ipv4/ip_input.c:207 (discriminator 1))
> ip_local_deliver_finish (net/ipv4/ip_input.c:241 (discriminator 1))
> ip_local_deliver (./include/linux/netfilter.h:325 ./include/linux/netfilter.h:319 net/ipv4/ip_input.c:262)
> ip_rcv (./include/net/dst.h:481 (discriminator 6) net/ipv4/ip_input.c:492 (discriminator 6) ./include/linux/netfilter.h:325 (discriminator 6) ./include/li)
> __netif_receive_skb_one_core (net/core/dev.c:6297 (discriminator 4))
> __netif_receive_skb (net/core/dev.c:6410)
> process_backlog (net/core/dev.c:6761)
> __napi_poll.constprop.0 (net/core/dev.c:7830)
> net_rx_action (net/core/dev.c:7893 net/core/dev.c:8050)
> handle_softirqs (kernel/softirq.c:645)
> __irq_exit_rcu (kernel/softirq.c:679 kernel/softirq.c:519 kernel/softirq.c:758)
> irq_exit_rcu (kernel/softirq.c:775)
> sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1062 (discriminator 35) arch/x86/kernel/apic/apic.c:1062 (discriminator 35))
> RIP: 0010:tcp_cong_avoid_ai (net/ipv4/tcp_cong.c:482)
>
> [...]
Here is the summary with links:
- [net,v6] net: ipv4: add zero check for snd_cwnd_clamp
https://git.kernel.org/netdev/net/c/363c8c79220d
You are awesome, thank you!
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