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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C22ABC2BB9A for ; Thu, 17 Dec 2020 01:42:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7551F23406 for ; Thu, 17 Dec 2020 01:42:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729041AbgLQBmB (ORCPT ); Wed, 16 Dec 2020 20:42:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:41384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725988AbgLQBmB (ORCPT ); Wed, 16 Dec 2020 20:42:01 -0500 Date: Wed, 16 Dec 2020 17:41:18 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608169280; bh=A0rKcafmrWfZmMmNs98pYScvdmdVpQNpcuZposdShPI=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=hB6oxGqHxGUs3jADyqRnryg7BOmmCcTG5QTbpitaacTtqoO4XtBpP/WHp0tnPLMLz wDua2AGgEIqqf0k14JnY2pt7MRdDQOEI0R78PlAKCcGW5xlDIjllaJ7ZWj/5+JGPuQ jiNM7c8bSndy2b5vfep1iALIxgm7RqgwNGL2JKt6O0jQDfwxNfWjRCVyunSNbtZ2wH q5eemMGy+xoCnR1IXMQYd0sc8XnolBPGjo9ZpIbzVX96qmyujzUGS0/I9eB+WxcByd VKk5+4VmgWbH7q6/kJ3A2vsqDwt8rZfd4FECl9m0CRMAhHjm4rMHX5VKEYJduVohxD 0DMQYJ81UF3Gw== From: Jaegeuk Kim To: Stanley Chu Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, kernel-team@android.com, cang@codeaurora.org, alim.akhtar@samsung.com, avri.altman@wdc.com, bvanassche@acm.org, martin.petersen@oracle.com Subject: Re: [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun Message-ID: References: <20201216190225.2769012-1-jaegeuk@kernel.org> <1608168474.10163.37.camel@mtkswgap22> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1608168474.10163.37.camel@mtkswgap22> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 12/17, Stanley Chu wrote: > Hi Jaegeuk, > > On Wed, 2020-12-16 at 11:02 -0800, Jaegeuk Kim wrote: > > From: Jaegeuk Kim > > > > This fixes the below livelock which is caused by calling a scsi command before > > ufshcd_scsi_unblock_requests() in ufshcd_ungate_work(). > > > > Workqueue: ufs_clk_gating_0 ufshcd_ungate_work > > Call trace: > > __switch_to+0x298/0x2bc > > __schedule+0x59c/0x760 > > schedule+0xac/0xf0 > > schedule_timeout+0x44/0x1b4 > > io_schedule_timeout+0x44/0x68 > > wait_for_common_io+0x7c/0x100 > > wait_for_completion_io+0x14/0x20 > > blk_execute_rq+0x94/0xd0 > > __scsi_execute+0x100/0x1c0 > > ufshcd_clear_ua_wlun+0x124/0x1c8 > > ufshcd_host_reset_and_restore+0x1d0/0x2cc > > ufshcd_link_recovery+0xac/0x134 > > ufshcd_uic_hibern8_exit+0x1e8/0x1f0 > > ufshcd_ungate_work+0xac/0x130 > > According to the latest mainstream kernel, once > ufshcd_uic_hibern8_exit() encounters error, instead, error handler work > will be scheduled without blocking ufshcd_uic_hibern8_exit(). In > addition, ufshcd_scsi_unblock_requests() would be invoked before leaving > ufshcd_uic_hibern8_exit(). So this stack is no longer existed. Oh, thank you for pointing this out. It seems the below patch made it. 4db7a2360597 ("scsi: ufs: Fix concurrency of error handler and other error recovery paths") Next time, I need to check upstream more carefully. :P > > Thanks, > Stanley Chu > > > process_one_work+0x270/0x47c > > worker_thread+0x27c/0x4d8 > > kthread+0x13c/0x320 > > ret_from_fork+0x10/0x18 > > > > Fixes: 1918651f2d7e ("scsi: ufs: Clear UAC for RPMB after ufshcd resets") > > Signed-off-by: Jaegeuk Kim > > --- > > drivers/scsi/ufs/ufshcd.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > > index e221add25a7e..b0998db1b781 100644 > > --- a/drivers/scsi/ufs/ufshcd.c > > +++ b/drivers/scsi/ufs/ufshcd.c > > @@ -1603,6 +1603,7 @@ static void ufshcd_ungate_work(struct work_struct *work) > > } > > unblock_reqs: > > ufshcd_scsi_unblock_requests(hba); > > + ufshcd_clear_ua_wluns(hba); > > } > > > > /** > > @@ -6913,7 +6914,7 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba) > > > > /* Establish the link again and restore the device */ > > err = ufshcd_probe_hba(hba, false); > > - if (!err) > > + if (!err && !hba->clk_gating.is_suspended) > > ufshcd_clear_ua_wluns(hba); > > out: > > if (err) > > @@ -8745,6 +8746,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) > > ufshcd_resume_clkscaling(hba); > > hba->clk_gating.is_suspended = false; > > hba->dev_info.b_rpm_dev_flush_capable = false; > > + ufshcd_clear_ua_wluns(hba); > > ufshcd_release(hba); > > out: > > if (hba->dev_info.b_rpm_dev_flush_capable) { > > @@ -8855,6 +8857,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) > > cancel_delayed_work(&hba->rpm_dev_flush_recheck_work); > > } > > > > + ufshcd_clear_ua_wluns(hba); > > + > > /* Schedule clock gating in case of no access to UFS device yet */ > > ufshcd_release(hba); > > >