From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6CAE023B0; Sat, 23 Aug 2025 01:32:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755912772; cv=none; b=pXIJV+o25KBtUpf9mdbJCBSm/3X0rbdAwypF931o9VcChWGvOm5RR1HyDK6vq0zWKa2f+AfQ+XB8lqMh8QCZ9cdjhtkQioodktn+4lsTHua7QF8uIS+JopL18NZ2nYothXF5RNIhAszwMJhINe4FW1ZvTrYVeCYqqYpw4Gs6+8Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755912772; c=relaxed/simple; bh=2bJlQ73zMhkZi/w8Svsurn0QcFTsicZAyfdxSWwE4Do=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=FsG1rvp5hX87SuwimFGEwYkKuBNhpxB8pBZm8HWZeZWz0MCkJV+GeqJBJ27aFzPyojR9cPELggUs8dTrbvAFGlEunWIP6L3CsQwJn7KotOiqScBPRHHexmZmqjdEYVgf/FPAilk0OGc2+yGPaSje1RDYZV6rtms+KSHfVTiq+Kg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rRRtUsef; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rRRtUsef" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D8AEC4CEED; Sat, 23 Aug 2025 01:32:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755912771; bh=2bJlQ73zMhkZi/w8Svsurn0QcFTsicZAyfdxSWwE4Do=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=rRRtUsefvqRilZsk4SwuF02AFFr2GQfdOlwmdU4PwfZgBWq1FwoDpJ6mcf366dt6E Hsa6JAKNkFk6n0Y49YlS1+4az7XQFUqYhrpDYWqyJDHIxFLtGRBCYo9ln/mWHSbpzf CfmVfCGccIUucsacuAt5aVsBtpB4DGkrc/tqHVjqldbrZIll8mGS5Gu39y+Au1z4B8 zYh8zKMRhRpmkc37d02IYfsdXBggdC+5ZpzC7/CzPfFvBGZom6fApxJWy4ZT5ZVnKe dCS5G7bMLgaHtIH8gkFBPy0b3KDnuqgzVQSdPVrLnS0xeAoLVlKl/7AA+VYL/tcgZW MzE3K0hITHyGw== Date: Fri, 22 Aug 2025 18:32:50 -0700 From: Jakub Kicinski To: Brett A C Sheffield Cc: regressions@lists.linux.dev, netdev@vger.kernel.org, stable@vger.kernel.org, davem@davemloft.net, dsahern@kernel.org, oscmaes92@gmail.com Subject: Re: [REGRESSION][BISECTED][PATCH] net: ipv4: fix regression in broadcast routes Message-ID: <20250822183250.2a9cb92c@kernel.org> In-Reply-To: <20250822165231.4353-4-bacs@librecast.net> References: <20250822165231.4353-4-bacs@librecast.net> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Thanks for bisecting and fixing! > The broadcast_pmtu.sh selftest provided with the original patch still > passes with this patch applied. Hm, yes, AFACT we're losing PMTU discovery but perhaps original commit wasn't concerned with that. Hopefully Oscar can comment. On Fri, 22 Aug 2025 16:50:51 +0000 Brett A C Sheffield wrote: > + if (type == RTN_BROADCAST) { > + /* ensure MTU value for broadcast routes is retained */ > + ip_dst_init_metrics(&rth->dst, res->fi->fib_metrics); You need to check if res->fi is actually set before using it Could you add a selftest / test case for the scenario we broke? selftests can be in C / bash / Python. If bash hopefully socat can be used to repro, cause it looks like wakeonlan is not very widely packaged.