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 2000EC04A68 for ; Sat, 30 Jul 2022 15:24:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234809AbiG3PYj (ORCPT ); Sat, 30 Jul 2022 11:24:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234460AbiG3PYi (ORCPT ); Sat, 30 Jul 2022 11:24:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B3EE13F8D for ; Sat, 30 Jul 2022 08:24:37 -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 223C360DE6 for ; Sat, 30 Jul 2022 15:24:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A1E2C433C1; Sat, 30 Jul 2022 15:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659194676; bh=5wFsTa9L3ImgyNyTKMZJBWjUZP8NVUJjQG4p1i7KlIE=; h=Subject:To:Cc:From:Date:From; b=klNRSuHlhSunPYAfwV2YPhTdQ3OrFsdjUGlMr+zh/BQjE1AuTowfeq14geHTys3Yb sRsWZJmO9z0ueq2liq1nVtx7mWXGn5t6Bflz2fNE1fyhFo+r5Ugp1sp2lTf0GsVh3h xA6zakoter+4R5zWIeUSsOf4LZdhJK/uWtS69L/I= Subject: FAILED: patch "[PATCH] scsi: ufs: core: Fix a race condition related to device" failed to apply to 5.15-stable tree To: bvanassche@acm.org, adrian.hunter@intel.com, avri.altman@wdc.com, beanhuo@micron.com, martin.petersen@oracle.com, stanley.chu@mediatek.com Cc: From: Date: Sat, 30 Jul 2022 17:24:27 +0200 Message-ID: <1659194667188248@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f5c2976e0cb0f6236013bfb479868531b04f61d4 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Wed, 20 Jul 2022 10:02:23 -0700 Subject: [PATCH] scsi: ufs: core: Fix a race condition related to device management If a device management command completion happens after wait_for_completion_timeout() times out and before ufshcd_clear_cmds() is called, then the completion code may crash on the complete() call in __ufshcd_transfer_req_compl(). Fix the following crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 Call trace: complete+0x64/0x178 __ufshcd_transfer_req_compl+0x30c/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 efi_header_end+0x110/0x680 __irq_exit_rcu+0x108/0x124 __handle_domain_irq+0x118/0x1e4 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 Link: https://lore.kernel.org/r/20220720170228.1598842-1-bvanassche@acm.org Fixes: 5a0b0cb9bee7 ("[SCSI] ufs: Add support for sending NOP OUT UPIU") Cc: Adrian Hunter Cc: Avri Altman Cc: Bean Huo Cc: Stanley Chu Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index c7b337480e3e..3d367be71728 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -2953,37 +2953,59 @@ ufshcd_dev_cmd_completion(struct ufs_hba *hba, struct ufshcd_lrb *lrbp) static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba, struct ufshcd_lrb *lrbp, int max_timeout) { - int err = 0; - unsigned long time_left; + unsigned long time_left = msecs_to_jiffies(max_timeout); unsigned long flags; + bool pending; + int err; +retry: time_left = wait_for_completion_timeout(hba->dev_cmd.complete, - msecs_to_jiffies(max_timeout)); + time_left); - spin_lock_irqsave(hba->host->host_lock, flags); - hba->dev_cmd.complete = NULL; if (likely(time_left)) { + /* + * The completion handler called complete() and the caller of + * this function still owns the @lrbp tag so the code below does + * not trigger any race conditions. + */ + hba->dev_cmd.complete = NULL; err = ufshcd_get_tr_ocs(lrbp); if (!err) err = ufshcd_dev_cmd_completion(hba, lrbp); - } - spin_unlock_irqrestore(hba->host->host_lock, flags); - - if (!time_left) { + } else { err = -ETIMEDOUT; dev_dbg(hba->dev, "%s: dev_cmd request timedout, tag %d\n", __func__, lrbp->task_tag); - if (!ufshcd_clear_cmds(hba, 1U << lrbp->task_tag)) + if (ufshcd_clear_cmds(hba, 1U << lrbp->task_tag) == 0) { /* successfully cleared the command, retry if needed */ err = -EAGAIN; - /* - * in case of an error, after clearing the doorbell, - * we also need to clear the outstanding_request - * field in hba - */ - spin_lock_irqsave(&hba->outstanding_lock, flags); - __clear_bit(lrbp->task_tag, &hba->outstanding_reqs); - spin_unlock_irqrestore(&hba->outstanding_lock, flags); + /* + * Since clearing the command succeeded we also need to + * clear the task tag bit from the outstanding_reqs + * variable. + */ + spin_lock_irqsave(&hba->outstanding_lock, flags); + pending = test_bit(lrbp->task_tag, + &hba->outstanding_reqs); + if (pending) { + hba->dev_cmd.complete = NULL; + __clear_bit(lrbp->task_tag, + &hba->outstanding_reqs); + } + spin_unlock_irqrestore(&hba->outstanding_lock, flags); + + if (!pending) { + /* + * The completion handler ran while we tried to + * clear the command. + */ + time_left = 1; + goto retry; + } + } else { + dev_err(hba->dev, "%s: failed to clear tag %d\n", + __func__, lrbp->task_tag); + } } return err;