netdev - Re: [PATCH net v3 1/2] net: ipv4: fix regression in local-broadcast routes

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Message-ID: <a42b28d5-e81e-4131-8c00-8925b097070a@kernel.org>
Date: Wed, 27 Aug 2025 10:09:48 -0600
From: David Ahern <dsahern@...nel.org>
To: Oscar Maes <oscmaes92@...il.com>, netdev@...r.kernel.org,
 bacs@...recast.net, brett@...recast.net, kuba@...nel.org
Cc: davem@...emloft.net, regressions@...ts.linux.dev, stable@...r.kernel.org
Subject: Re: [PATCH net v3 1/2] net: ipv4: fix regression in local-broadcast
 routes

On 8/27/25 12:23 AM, Oscar Maes wrote:
> Commit 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes")
> introduced a regression where local-broadcast packets would have their
> gateway set in __mkroute_output, which was caused by fi = NULL being
> removed.
> 
> Fix this by resetting the fib_info for local-broadcast packets. This
> preserves the intended changes for directed-broadcast packets.
> 
> Cc: stable@...r.kernel.org
> Fixes: 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes")
> Reported-by: Brett A C Sheffield <bacs@...recast.net>
> Closes: https://lore.kernel.org/regressions/20250822165231.4353-4-bacs@librecast.net
> Signed-off-by: Oscar Maes <oscmaes92@...il.com>
> ---
> Link to discussion:
> https://lore.kernel.org/netdev/20250822165231.4353-4-bacs@librecast.net/
> 
> Thanks to Brett Sheffield for finding the regression and writing
> the initial fix!
> 
>  net/ipv4/route.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@...nel.org>