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 6D933C41513 for ; Tue, 25 Jul 2023 07:08:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231428AbjGYHIP (ORCPT ); Tue, 25 Jul 2023 03:08:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231387AbjGYHIO (ORCPT ); Tue, 25 Jul 2023 03:08:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2052ABD; Tue, 25 Jul 2023 00:08:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B0C4C61129; Tue, 25 Jul 2023 07:08:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92C13C433C8; Tue, 25 Jul 2023 07:08:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690268893; bh=8ZO+dQLtUiBc7Ah68ZPlpmAFo7aFZA5cxmTFAGgJ4qQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tz1wvA2lxwAsPqVJtqbtnialvr10PrdMB1LuHZw47XVu1YM0unJi6kQQF1HczgJAC UgCBGXe3vZUin1qlo5WT/CIIDHxsIwhiSfQOVdm+fbtH0LQleRIJ+PKVGgfNRODelI Vn1hCwrXUEOBpUffiR2rRiCZMyPpXB1MXEfAN1XQ= Date: Tue, 25 Jul 2023 09:08:10 +0200 From: Greg KH To: Alex Elder Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dianders@chromium.org, caleb.connolly@linaro.org, mka@chromium.org, evgreen@chromium.org, andersson@kernel.org, quic_cpratapa@quicinc.com, quic_avuyyuru@quicinc.com, quic_jponduru@quicinc.com, quic_subashab@quicinc.com, elder@kernel.org, netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH net] net: ipa: only reset hashed tables when supported Message-ID: <2023072538-corned-falsify-d054@gregkh> References: <20230724224106.1688869-1-elder@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230724224106.1688869-1-elder@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, Jul 24, 2023 at 05:41:06PM -0500, Alex Elder wrote: > Last year, the code that manages GSI channel transactions switched > from using spinlock-protected linked lists to using indexes into the > ring buffer used for a channel. Recently, Google reported seeing > transaction reference count underflows occasionally during shutdown. > > Doug Anderson found a way to reproduce the issue reliably, and > bisected the issue to the commit that eliminated the linked lists > and the lock. The root cause was ultimately determined to be > related to unused transactions being committed as part of the modem > shutdown cleanup activity. Unused transactions are not normally > expected (except in error cases). > > The modem uses some ranges of IPA-resident memory, and whenever it > shuts down we zero those ranges. In ipa_filter_reset_table() a > transaction is allocated to zero modem filter table entries. If > hashing is not supported, hashed table memory should not be zeroed. > But currently nothing prevents that, and the result is an unused > transaction. Something similar occurs when we zero routing table > entries for the modem. > > By preventing any attempt to clear hashed tables when hashing is not > supported, the reference count underflow is avoided in this case. > > Note that there likely remains an issue with properly freeing unused > transactions (if they occur due to errors). This patch addresses > only the underflows that Google originally reported. > > Fixes: d338ae28d8a8 ("net: ipa: kill all other transaction lists") > Cc: # 6.1.x > Tested-by: Douglas Anderson > Signed-off-by: Alex Elder > --- > drivers/net/ipa/ipa_table.c | 26 ++++++++++++++------------ > 1 file changed, 14 insertions(+), 12 deletions(-) You sent 2 different versions of this patch? Which one is for what tree? Is this in Linus's tree already? If so, what's the git id? confused, greg k-h