From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD3EAC433B4 for ; Mon, 12 Apr 2021 09:35:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 708F76120F for ; Mon, 12 Apr 2021 09:35:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237433AbhDLJfc (ORCPT ); Mon, 12 Apr 2021 05:35:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:35900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240284AbhDLJKL (ORCPT ); Mon, 12 Apr 2021 05:10:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3930D61278; Mon, 12 Apr 2021 09:05:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618218309; bh=e2GOtONqIKPscLHRK3BMkU515TNI6jGtQk8adjOJPJU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Evrd+T9yVrPXy24pE/3OjBBqYtZsAgIrMdFy5ayr/6VXTTdGHgk+v7UNA8Sa9imOH xcrPNqHWStHEAhN/E5ONPGD+2u6+W880yJ3z2B6Lx8XvIaM4S/V4aTUjKJvYHT2hW9 7m/UA2mB3z8Z6C0bnzIldE19OMikGPhqlbCATNzU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ong Boon Leong , Jesper Dangaard Brouer , "David S. Miller" , Sasha Levin Subject: [PATCH 5.11 149/210] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model Date: Mon, 12 Apr 2021 10:40:54 +0200 Message-Id: <20210412084020.951775534@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084016.009884719@linuxfoundation.org> References: <20210412084016.009884719@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ong Boon Leong [ Upstream commit 622d13694b5f048c01caa7ba548498d9880d4cb0 ] xdp_return_frame() may be called outside of NAPI context to return xdpf back to page_pool. xdp_return_frame() calls __xdp_return() with napi_direct = false. For page_pool memory model, __xdp_return() calls xdp_return_frame_no_direct() unconditionally and below false negative kernel BUG throw happened under preempt-rt build: [ 430.450355] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/3884 [ 430.451678] caller is __xdp_return+0x1ff/0x2e0 [ 430.452111] CPU: 0 PID: 3884 Comm: modprobe Tainted: G U E 5.12.0-rc2+ #45 Changes in v2: - This patch fixes the issue by making xdp_return_frame_no_direct() is only called if napi_direct = true, as recommended for better by Jesper Dangaard Brouer. Thanks! Fixes: 2539650fadbf ("xdp: Helpers for disabling napi_direct of xdp_return_frame") Signed-off-by: Ong Boon Leong Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/xdp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/xdp.c b/net/core/xdp.c index 3a8c9ab4ecbe..a86bc3660729 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -350,7 +350,8 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); page = virt_to_head_page(data); - napi_direct &= !xdp_return_frame_no_direct(); + if (napi_direct && xdp_return_frame_no_direct()) + napi_direct = false; page_pool_put_full_page(xa->page_pool, page, napi_direct); rcu_read_unlock(); break; -- 2.30.2