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@vger.kernel.org
Fixes: 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes")
Reported-by: Brett A C Sheffield <redacted>
Closes: https://lore.kernel.org/regressions/20250822165231.4353-4-bacs@librecast.net (local)
Signed-off-by: Oscar Maes <redacted>
---
Link to discussion:
https://lore.kernel.org/netdev/20250822165231.4353-4-bacs@librecast.net/ (local)

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@kernel.org>