From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (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 A7E5037CD5B for ; Tue, 3 Mar 2026 03:14:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772507652; cv=none; b=pxocX9l4zottAjxKrcZGUw8XFolCJgT8o2qknG8n2ComeJ1StvbAA/py0q4TENBdTDxj5Nh5SO+AJf8QkO+5IlXIVL5ji9YnET8GauL1gAeOQ67yttVMN2y+sg9W6trjZrmJwMM3IKhDcFoZuWvME9rN4PANrFupSI9PHjux1js= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772507652; c=relaxed/simple; bh=g0zsyX5L4EjBrrYoCc53vN2N/abj8Y7XpyE4Qa9FYoU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sJ0lZJss3V6cueWwdqVMC/Mw9XtYoGrXC4esQKLk2IdPmMkhXJMfNPASAdPKj8/Jc/v2Qvvatg48ikNXHikaQaUFHSbK0A0H6ncCtxKxwZqsbltOk1COWnbekak+sVJy+A9Hh2jevBbUom5+QwGopx8BKPaCdmWMudYKY/XwAvI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=TBRG1ocm; arc=none smtp.client-ip=91.218.175.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="TBRG1ocm" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772507648; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Pya4KvUPnvgrc1pzLQK2NnEUBs5WZG3BUAj2N7xy7TE=; b=TBRG1ocmDMDIs32tTlSpGaW/vxUxiqtDFm/1EAYS5bnDLabf44SzGa029DRcX+LIY+tBS7 jp+od9Fp1iwHFXS4UZayvYCJBBiCc+Did1vVhURCBfbkoX1s4EoNCZc5Zj3eofakL9zJqQ KglecdUEb9XT3yY7ALXwtXXqBM4BQfs= From: Jiayuan Chen To: netdev@vger.kernel.org Cc: jiayuna.chen@linux.dev, jiayuna.chen@shopee.com, idosch@nvidia.com, Jiayuan Chen , "David S. Miller" , David Ahern , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH net v3 2/2] selftests: net: add test for IPv4 route with loopback IPv6 nexthop Date: Tue, 3 Mar 2026 11:13:15 +0800 Message-ID: <20260303031318.339716-3-jiayuan.chen@linux.dev> In-Reply-To: <20260303031318.339716-1-jiayuan.chen@linux.dev> References: <20260303031318.339716-1-jiayuan.chen@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Jiayuan Chen Add a regression test for a panic triggered when an IPv4 route references a loopback IPv6 nexthop object. Without the fix, this sequence causes a NULL pointer dereference in __mkroute_output() because nhc_pcpu_rth_output is not allocated for the nexthop. ./fib_nexthops.sh Tests passed: 249 Tests failed: 0 Tests skipped: 2 Reviewed-by: Ido Schimmel Signed-off-by: Jiayuan Chen --- tools/testing/selftests/net/fib_nexthops.sh | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh index 21026b667667..6eb7f95e70e1 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -1672,6 +1672,17 @@ ipv4_withv6_fcnal() run_cmd "$IP ro replace 172.16.101.1/32 via inet6 2001:db8:50::1 dev veth1" log_test $? 2 "IPv4 route with invalid IPv6 gateway" + + # Test IPv4 route with loopback IPv6 nexthop + # Regression test: loopback IPv6 nexthop was misclassified as reject + # route, skipping nhc_pcpu_rth_output allocation, causing panic when + # an IPv4 route references it and triggers __mkroute_output(). + run_cmd "$IP -6 nexthop add id 20 dev lo" + run_cmd "$IP ro add 172.20.20.0/24 nhid 20" + run_cmd "ip netns exec $me ping -c1 -W1 172.20.20.1" + log_test $? 1 "IPv4 route with loopback IPv6 nexthop (no crash)" + run_cmd "$IP ro del 172.20.20.0/24" + run_cmd "$IP nexthop del id 20" } ipv4_fcnal_runtime() -- 2.43.0