From patchwork Mon Jun 13 21:44:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 581608 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 83515C43334 for ; Mon, 13 Jun 2022 21:45:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239622AbiFMVpg (ORCPT ); Mon, 13 Jun 2022 17:45:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234131AbiFMVpY (ORCPT ); Mon, 13 Jun 2022 17:45:24 -0400 Received: from mail-pg1-f172.google.com (mail-pg1-f172.google.com [209.85.215.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D3456463 for ; Mon, 13 Jun 2022 14:45:23 -0700 (PDT) Received: by mail-pg1-f172.google.com with SMTP id l4so5664340pgh.13 for ; Mon, 13 Jun 2022 14:45:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=RlJQWaQtzKYLaJO2jTeTrMzOBITTjl5zGC+qrwjiNv8=; b=aJG3SVTv5sfpHy/LS/WGevNE+PzKJbkunqUK2jcbuB3X5n4RQH/2bdCPVXy680poA0 bn33jIW8SJWWD6MD0tToe34lLz/itsNYaC/4dghGqDAlPToUXxVthBRy0A+Fz0TgptjN OpkQ6EXveRFjdkW9mV2ReGTlywV3gyhEHhqFkicMbEkZVdGR/vWlTcIclKJM9oECVLFP BsWtyxhLEGUBt3hpxTn/L9g/P7bbaV5N58zWADYl6KUP80xqe2HhACeLhoSNaKUmJMij CGnU+6iSOFpi0t/ypgqLKEPfJ1wcWfp4g+Qw2OXolNWOFtIVzcxHsl11i9/OJ2dH0wQd vfwg== X-Gm-Message-State: AOAM530jXZ0UsVO3wpJGoAfNXUTjkcikkHRkeVXoqJaidAKJ9P0729tJ O4wBTI9tIqf6kKC6rhEU1RE= X-Google-Smtp-Source: ABdhPJxMgl8HkMzIxO4Kh66eF6Z15nP+OhNOFpkG1cEwQzxW6Etx/rMk0HqCQDOxT3fpg92mgC5aLA== X-Received: by 2002:a05:6a00:10d3:b0:4fe:5d:75c8 with SMTP id d19-20020a056a0010d300b004fe005d75c8mr1364549pfu.6.1655156722845; Mon, 13 Jun 2022 14:45:22 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:6862:a290:1a09:5af5]) by smtp.gmail.com with ESMTPSA id ji2-20020a170903324200b001622c377c3esm5585833plb.117.2022.06.13.14.45.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jun 2022 14:45:22 -0700 (PDT) From: Bart Van Assche To: "Martin K . Petersen" Cc: Jaegeuk Kim , Adrian Hunter , linux-scsi@vger.kernel.org, Bart Van Assche , "James E.J. Bottomley" , Bean Huo , Avri Altman Subject: [PATCH v2 3/3] scsi: ufs: Fix a race between the interrupt handler and the reset handler Date: Mon, 13 Jun 2022 14:44:42 -0700 Message-Id: <20220613214442.212466-4-bvanassche@acm.org> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog In-Reply-To: <20220613214442.212466-1-bvanassche@acm.org> References: <20220613214442.212466-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Prevent that both the interrupt handler and the reset handler try to complete a request at the same time. This patch is the result of an analysis of the following crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000120 CPU: 0 PID: 0 Comm: swapper/0 Tainted: G OE 5.10.107-android13-4-00051-g1e48e8970cca-ab8664745 #1 pc : ufshcd_release_scsi_cmd+0x30/0x46c lr : __ufshcd_transfer_req_compl+0x4fc/0x9c0 Call trace: ufshcd_release_scsi_cmd+0x30/0x46c __ufshcd_transfer_req_compl+0x4fc/0x9c0 ufshcd_poll+0xf0/0x208 ufshcd_sl_intr+0xb8/0xf0 ufshcd_intr+0x168/0x2f4 __handle_irq_event_percpu+0xa0/0x30c handle_irq_event+0x84/0x178 handle_fasteoi_irq+0x150/0x2e8 __handle_domain_irq+0x114/0x1e4 gic_handle_irq.31846+0x58/0x300 el1_irq+0xe4/0x1c0 cpuidle_enter_state+0x3ac/0x8c4 do_idle+0x2fc/0x55c cpu_startup_entry+0x84/0x90 kernel_init+0x0/0x310 start_kernel+0x0/0x608 start_kernel+0x4ec/0x608 Signed-off-by: Bart Van Assche --- drivers/ufs/core/ufshcd.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index b7120c5f0920..ff3abda91bb6 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -6975,14 +6975,14 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba, } /** - * ufshcd_eh_device_reset_handler - device reset handler registered to - * scsi layer. + * ufshcd_eh_device_reset_handler() - Reset a single logical unit. * @cmd: SCSI command pointer * * Returns SUCCESS/FAILED */ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd) { + unsigned long flags, pending_reqs = 0, not_cleared = 0; struct Scsi_Host *host; struct ufs_hba *hba; u32 pos; @@ -7001,14 +7001,24 @@ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd) } /* clear the commands that were pending for corresponding LUN */ - for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs) { - if (hba->lrb[pos].lun == lun) { - err = ufshcd_clear_cmds(hba, 1U << pos); - if (err) - break; - __ufshcd_transfer_req_compl(hba, 1U << pos); - } + spin_lock_irqsave(&hba->outstanding_lock, flags); + for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs) + if (hba->lrb[pos].lun == lun) + __set_bit(pos, &pending_reqs); + hba->outstanding_reqs &= ~pending_reqs; + spin_unlock_irqrestore(&hba->outstanding_lock, flags); + + if (ufshcd_clear_cmds(hba, pending_reqs) < 0) { + spin_lock_irqsave(&hba->outstanding_lock, flags); + not_cleared = pending_reqs & + ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL); + hba->outstanding_reqs |= not_cleared; + spin_unlock_irqrestore(&hba->outstanding_lock, flags); + + dev_err(hba->dev, "%s: failed to clear requests %#lx\n", + __func__, not_cleared); } + __ufshcd_transfer_req_compl(hba, pending_reqs & ~not_cleared); out: hba->req_abort_count = 0;