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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 503BAC433EF for ; Mon, 21 Mar 2022 13:54:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348245AbiCUNzg (ORCPT ); Mon, 21 Mar 2022 09:55:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347775AbiCUNzO (ORCPT ); Mon, 21 Mar 2022 09:55:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE5905F64; Mon, 21 Mar 2022 06:53:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6A9116129D; Mon, 21 Mar 2022 13:53:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CD96C340F2; Mon, 21 Mar 2022 13:53:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647870827; bh=ORgOXrbErGzG4bsiU02n8K34kQWixB1gzAnSuiyDSKY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DQwgQAqYwBh+T99J1ZjMnbjfltY38PIIMDojZegJVhA4+f4+rUotsSXU0GVs93idf wu4x7vkHZ3wej3MPx6M2wpqPPAszPIA/vZgpcgv+KsCTWRwcKVFh7ba1E/dma5HZGK H69jBm/F6tR2PwSZf7uSwEOBQgmVEBiaD5PPufXU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Niels Dossche , Martin Habets , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 09/16] sfc: extend the locking on mcdi->seqno Date: Mon, 21 Mar 2022 14:51:39 +0100 Message-Id: <20220321133216.925997549@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220321133216.648316863@linuxfoundation.org> References: <20220321133216.648316863@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: Niels Dossche [ Upstream commit f1fb205efb0ccca55626fd4ef38570dd16b44719 ] seqno could be read as a stale value outside of the lock. The lock is already acquired to protect the modification of seqno against a possible race condition. Place the reading of this value also inside this locking to protect it against a possible race condition. Signed-off-by: Niels Dossche Acked-by: Martin Habets Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/sfc/mcdi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c index 241520943ada..221798499e24 100644 --- a/drivers/net/ethernet/sfc/mcdi.c +++ b/drivers/net/ethernet/sfc/mcdi.c @@ -162,9 +162,9 @@ static void efx_mcdi_send_request(struct efx_nic *efx, unsigned cmd, /* Serialise with efx_mcdi_ev_cpl() and efx_mcdi_ev_death() */ spin_lock_bh(&mcdi->iface_lock); ++mcdi->seqno; + seqno = mcdi->seqno & SEQ_MASK; spin_unlock_bh(&mcdi->iface_lock); - seqno = mcdi->seqno & SEQ_MASK; xflags = 0; if (mcdi->mode == MCDI_MODE_EVENTS) xflags |= MCDI_HEADER_XFLAGS_EVREQ; -- 2.34.1