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 BD145C4332F for ; Mon, 5 Dec 2022 17:38:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230037AbiLERir (ORCPT ); Mon, 5 Dec 2022 12:38:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230123AbiLERiq (ORCPT ); Mon, 5 Dec 2022 12:38:46 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD9BA9FE0 for ; Mon, 5 Dec 2022 09:38:41 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 5C357B8119F for ; Mon, 5 Dec 2022 17:38:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 403ECC433D6; Mon, 5 Dec 2022 17:38:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670261919; bh=DiELGqOeqRCXeJFQiJ4pqJlVnhWHvx8K7+9u4AOMvpM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Uyo90APpQG4zqe7TkGs/DAg6D7Er/0KzY5ZNTiU3l+gA3rephyej9bFuZwHtvgJjC VeJ5QjM0rQeV5ML63jqktSphNaVUHHzclb5OL7mCHeZW1xxEHmhy8PLW5Le4wL/arS qEMd2FsxSAk89OLrxfln497CF8XcjOYaTD3EI7EVvGOj/40pkQguFK/sskKNPmX62X XxadYBLv+8DQHsl0ITZ3j0CQW87ptppFC6kUEFJMmwYjpQAUHKt9bkBxGrn4zYibMt BICShv0o8TEhd+9rJWIspTrb7+N0Fmh4w/yP2UNm9fxRGadhQNbyU6Tbx6Z58sLsv7 jYnmu2Q5wzNcQ== Date: Mon, 5 Dec 2022 19:38:34 +0200 From: Leon Romanovsky To: Lorenzo Bianconi Cc: Lorenzo Bianconi , netdev@vger.kernel.org, nbd@nbd.name, john@phrozen.org, sean.wang@mediatek.com, Mark-MC.Lee@mediatek.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, matthias.bgg@gmail.com, linux-mediatek@lists.infradead.org, sujuan.chen@mediatek.com Subject: Re: [PATCH v2 net-next] net: ethernet: mtk_wed: fix possible deadlock if mtk_wed_wo_init fails Message-ID: References: <5a29aae6c4a26e807844210d4ddac7950ca5f63d.1670238731.git.lorenzo@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Dec 05, 2022 at 06:05:49PM +0100, Lorenzo Bianconi wrote: > > On Mon, Dec 05, 2022 at 12:14:41PM +0100, Lorenzo Bianconi wrote: > > > Introduce __mtk_wed_detach() in order to avoid a possible deadlock in > > > mtk_wed_attach routine if mtk_wed_wo_init fails. > > > Check wo pointer is properly allocated before running mtk_wed_wo_rese= t() > > > and mtk_wed_wo_deinit() in __mtk_wed_detach routine. > > > Honor mtk_wed_mcu_send_msg return value in mtk_wed_wo_reset(). > > >=20 > > > Fixes: 4c5de09eb0d0 ("net: ethernet: mtk_wed: add configure wed wo su= pport") > > > Signed-off-by: Lorenzo Bianconi > > > --- > > > Changes since v1: > > > - move wo pointer checks in __mtk_wed_detach() > > > --- > > > drivers/net/ethernet/mediatek/mtk_wed.c | 30 ++++++++++++++-----= -- > > > drivers/net/ethernet/mediatek/mtk_wed_mcu.c | 3 +++ > > > 2 files changed, 23 insertions(+), 10 deletions(-) > > >=20 > > > diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/et= hernet/mediatek/mtk_wed.c > > > index d041615b2bac..2ce9fbb1c66d 100644 > > > --- a/drivers/net/ethernet/mediatek/mtk_wed.c > > > +++ b/drivers/net/ethernet/mediatek/mtk_wed.c > > > @@ -174,9 +174,10 @@ mtk_wed_wo_reset(struct mtk_wed_device *dev) > > > mtk_wdma_tx_reset(dev); > > > mtk_wed_reset(dev, MTK_WED_RESET_WED); > > > =20 > > > - mtk_wed_mcu_send_msg(wo, MTK_WED_MODULE_ID_WO, > > > - MTK_WED_WO_CMD_CHANGE_STATE, &state, > > > - sizeof(state), false); > > > + if (mtk_wed_mcu_send_msg(wo, MTK_WED_MODULE_ID_WO, > > > + MTK_WED_WO_CMD_CHANGE_STATE, &state, > > > + sizeof(state), false)) > > > + return; > > > =20 > > > if (readx_poll_timeout(mtk_wed_wo_read_status, dev, val, > > > val =3D=3D MTK_WED_WOIF_DISABLE_DONE, > > > @@ -576,12 +577,10 @@ mtk_wed_deinit(struct mtk_wed_device *dev) > > > } > > > =20 > > > static void > > > -mtk_wed_detach(struct mtk_wed_device *dev) > > > +__mtk_wed_detach(struct mtk_wed_device *dev) > > > { > > > struct mtk_wed_hw *hw =3D dev->hw; > > > =20 > > > - mutex_lock(&hw_lock); > > > - > > > mtk_wed_deinit(dev); > > > =20 > > > mtk_wdma_rx_reset(dev); > > > @@ -590,9 +589,11 @@ mtk_wed_detach(struct mtk_wed_device *dev) > > > mtk_wed_free_tx_rings(dev); > > > =20 > > > if (mtk_wed_get_rx_capa(dev)) { > > > - mtk_wed_wo_reset(dev); > > > + if (hw->wed_wo) > > > + mtk_wed_wo_reset(dev); > > > mtk_wed_free_rx_rings(dev); > > > - mtk_wed_wo_deinit(hw); > > > + if (hw->wed_wo) > > > + mtk_wed_wo_deinit(hw); > > > } > > > =20 > > > if (dev->wlan.bus_type =3D=3D MTK_WED_BUS_PCIE) { > > > @@ -612,6 +613,13 @@ mtk_wed_detach(struct mtk_wed_device *dev) > > > module_put(THIS_MODULE); > > > =20 > > > hw->wed_dev =3D NULL; > > > +} > > > + > > > +static void > > > +mtk_wed_detach(struct mtk_wed_device *dev) > > > +{ > > > + mutex_lock(&hw_lock); > > > + __mtk_wed_detach(dev); > > > mutex_unlock(&hw_lock); > > > } > > > =20 > > > @@ -1490,8 +1498,10 @@ mtk_wed_attach(struct mtk_wed_device *dev) > > > ret =3D mtk_wed_wo_init(hw); > > > } > > > out: > > > - if (ret) > > > - mtk_wed_detach(dev); > > > + if (ret) { > > > + dev_err(dev->hw->dev, "failed to attach wed device\n"); > > > + __mtk_wed_detach(dev); > > > + } > > > unlock: > > > mutex_unlock(&hw_lock); > > > =20 > > > diff --git a/drivers/net/ethernet/mediatek/mtk_wed_mcu.c b/drivers/ne= t/ethernet/mediatek/mtk_wed_mcu.c > > > index f9539e6233c9..3dd02889d972 100644 > > > --- a/drivers/net/ethernet/mediatek/mtk_wed_mcu.c > > > +++ b/drivers/net/ethernet/mediatek/mtk_wed_mcu.c > > > @@ -207,6 +207,9 @@ int mtk_wed_mcu_msg_update(struct mtk_wed_device = *dev, int id, void *data, > > > if (dev->hw->version =3D=3D 1) > > > return 0; > > > =20 > > > + if (!wo) > > > + return -ENODEV; > > > + > >=20 > > Can you please help me to understand how and when this mtk_wed_mcu_msg_= update() > > function is called? > >=20 > > I see this line .msg_update =3D mtk_wed_mcu_msg_update, and > > relevant mtk_wed_device_update_msg() define, but nothing calls to this > > define. >=20 > mtk_wed_device_update_msg() is currently run by mt7915 driver in > mt7915_mcu_wed_enable_rx_stats() and in mt76_connac_mcu_sta_wed_update(). I see, I didn't fetch latest net-next. > At the moment we always run mtk_wed_mcu_msg_update with non-NULL wo point= er, > but I would prefer to add this safety check. If it is impossible, please add WARN_ON(!wo) instead of "if ...". It describes better what is expected here. Thanks >=20 > Regards, > Lorenzo >=20 > >=20 > >=20 > >=20 > > > return mtk_wed_mcu_send_msg(wo, MTK_WED_MODULE_ID_WO, id, data, len, > > > true); > > > } > > > --=20 > > > 2.38.1 > > >=20 > >=20