From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 624745038E5; Tue, 13 Oct 2026 12:02:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791892959; cv=none; b=Jzj+F9mrWQ3dLD/jppL4LuG2+xEH2P6r4oYXmXlskp/tq6y7o+4zztC+REY2FvspOz/HR0EClhOn1J3Vr4R/hDmwOkAhpITw+yMw8wKgIz+7C+/fXRLvlwMgLzfVvHa0MC3yfp+z/V679Q+cZwaggrkm/TrrmWuHqQs9yKxxQpM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791892959; c=relaxed/simple; bh=AUxQhShP7B68Sgxdj9Z+OZjTKn1ZyvFOqQRhkW8SmCQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f1CY4809UgtqJX8RnnRqJ2UVVeyISubYNltvL+6q+qwEbGdqidN1fUHVF6gAG4dt2byT7f1QZQBEhsxvbaJyuzB0e2X0hG0I4YYCbqDWAUEOtatXVvsrcPll/KfcUjjvz2sauVN9HrtjfeMS9RQDmgXo/ZDGx8HkkVxOFGPvPNQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2YEvS25r; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2YEvS25r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D04B1F00893; Tue, 13 Oct 2026 12:02:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791892958; bh=p50bq3bWUnuw5aZL9C2GO0VquJSDy3bqVvsHX1XVQak=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=2YEvS25rVnJFwk5bT2Z7uMAP37oWiPu9mWUifkJSV321ct+kzemt+uk2kUrdwaX6v qnN9NebZizOTShJeCo15HTkg9eYqDrefPVIv+ATWib/6lT5k6iaesgjyKHrdlAeVmR EM9CVra7e3L+Nc4y9UZ/8iU8cLnp+AGI3vTVLUlo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ido Schimmel , Daehyeon Ko <4ncienth@gmail.com>, Jakub Kicinski Subject: [PATCH 6.18 021/621] ipv4: do not warn on route notification size race Date: Tue, 13 Oct 2026 13:30:16 +0200 Message-ID: <20261013112921.369719616@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daehyeon Ko <4ncienth@gmail.com> commit e02a5b6588161673ef75a4bc5cdfb62bd493374d upstream. Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware flags are changed") added asynchronous route notifications for hardware flag changes. fib_alias_hw_flags_set() sizes the skb with fib_nlmsg_size() and later fills it with fib_dump_info() while holding only RCU. With nexthop compatibility mode enabled, a concurrent replacement can grow the group between these independent snapshots. fib_dump_info() can then legitimately return -EMSGSIZE, so the warning does not prove a sizing bug. Remove the warning. The existing error path still frees the skb and reports the error to listeners. Fixes: 680aea08e78c ("net: ipv4: Emit notification when fib hardware flags are changed") Reported-by: Ido Schimmel Link: https://lore.kernel.org/netdev/20261004082043.GB92032@shredder/ Suggested-by: Ido Schimmel Cc: stable@vger.kernel.org Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Link: https://patch.msgid.link/b7e203fc5867651cb67ef84aa03e082f0f76008e.1791423190.git.4ncienth@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv4/fib_trie.c | 2 -- 1 file changed, 2 deletions(-) --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -1079,8 +1079,6 @@ void fib_alias_hw_flags_set(struct net * err = fib_dump_info(skb, 0, 0, RTM_NEWROUTE, fri, 0); if (err < 0) { - /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ - WARN_ON(err == -EMSGSIZE); kfree_skb(skb); goto errout; }