Re: 5.15.190-rc1 review

Upstream commit: 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes")

introduces a regression which breaks IPv4 broadcast, which stops WOL working (breaking my CI system), among other things:

https://lore.kernel.org/regressions/20250822165231.4353-4-bacs@librecast.net

Mainline fix pending.

# Librecast Test Results

010/010 [ OK ] libmld 120/120 [ OK ] liblibrecast

CPU/kernel: Linux auntie 5.15.190-rc1-00645-ge09f9302f92d #48 SMP Tue Aug 26 11:48:25 -00 2025 x86_64 AMD Ryzen 9 9950X 16-Core Processor AuthenticAMD GNU/Linux

Tested-by: Brett A C Sheffield bacs@librecast.net