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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0D21C433F5 for ; Mon, 11 Oct 2021 14:17:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA93560238 for ; Mon, 11 Oct 2021 14:17:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244739AbhJKOSP (ORCPT ); Mon, 11 Oct 2021 10:18:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:38740 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244386AbhJKOPb (ORCPT ); Mon, 11 Oct 2021 10:15:31 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A93A66135E; Mon, 11 Oct 2021 14:05:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633961127; bh=AU+oTuC3resiRst+ay17ossOmlzzap2TC1pBpHixHXI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uAA4Q+PDutIeD4Kj53KBbIIDjkuR8CncrMKvWPZhDD2TGxs4BPdpMe/xCOCxR0Nh8 GFcUONi8hHLh2q5rgJ+yv4Y10+Jv5zKiDX4TvJVZ1+bhc/8A+NCCyioMg+gEZqInKQ TevOWI5j7ihwK9z/M9ffSXbYm4i+lsg2NE+sjnRo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefan Assmann , Jiri Benc , Jesse Brandeburg , Dave Switzer , Tony Nguyen , Sasha Levin Subject: [PATCH 4.19 24/28] i40e: fix endless loop under rtnl Date: Mon, 11 Oct 2021 15:47:14 +0200 Message-Id: <20211011134641.498616131@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211011134640.711218469@linuxfoundation.org> References: <20211011134640.711218469@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: Jiri Benc [ Upstream commit 857b6c6f665cca9828396d9743faf37fd09e9ac3 ] The loop in i40e_get_capabilities can never end. The problem is that although i40e_aq_discover_capabilities returns with an error if there's a firmware problem, the returned error is not checked. There is a check for pf->hw.aq.asq_last_status but that value is set to I40E_AQ_RC_OK on most firmware problems. When i40e_aq_discover_capabilities encounters a firmware problem, it will encounter the same problem on its next invocation. As the result, the loop becomes endless. We hit this with I40E_ERR_ADMIN_QUEUE_TIMEOUT but looking at the code, it can happen with a range of other firmware errors. I don't know what the correct behavior should be: whether the firmware should be retried a few times, or whether pf->hw.aq.asq_last_status should be always set to the encountered firmware error (but then it would be pointless and can be just replaced by the i40e_aq_discover_capabilities return value). However, the current behavior with an endless loop under the rtnl mutex(!) is unacceptable and Intel has not submitted a fix, although we explained the bug to them 7 months ago. This may not be the best possible fix but it's better than hanging the whole system on a firmware bug. Fixes: 56a62fc86895 ("i40e: init code and hardware support") Tested-by: Stefan Assmann Signed-off-by: Jiri Benc Reviewed-by: Jesse Brandeburg Tested-by: Dave Switzer Signed-off-by: Tony Nguyen Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/i40e/i40e_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 246734be5177..8f7d3af75ed6 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -9068,7 +9068,7 @@ static int i40e_get_capabilities(struct i40e_pf *pf, if (pf->hw.aq.asq_last_status == I40E_AQ_RC_ENOMEM) { /* retry with a larger buffer */ buf_len = data_size; - } else if (pf->hw.aq.asq_last_status != I40E_AQ_RC_OK) { + } else if (pf->hw.aq.asq_last_status != I40E_AQ_RC_OK || err) { dev_info(&pf->pdev->dev, "capability discovery failed, err %s aq_err %s\n", i40e_stat_str(&pf->hw, err), -- 2.33.0