From 639358dd6e2f7e5e9f7e66b828bf043fa3c7bbf2 Mon Sep 17 00:00:00 2001
From: Can Guo <cang@codeaurora.org>
Date: Sat, 9 Jan 2021 12:37:40 +0800
Subject: [PATCH] scsi: ufs: Reproduce race condition btw sysfs access and
 shutdown

Reproduce race condition btw sysfs access and shutdown

Usage:

Signed-off-by: Can Guo <cang@codeaurora.org>

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 92a63ee..a29a490 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -59,6 +59,8 @@ static ssize_t rpm_lvl_show(struct device *dev,
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 
+	BUG_ON(hba->shutting_down);
+
 	return sprintf(buf, "%d\n", hba->rpm_lvl);
 }
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 698e8d2..210fa5c 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8277,6 +8277,11 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 {
 	int ret = 0;
 
+	hba->shutting_down = true;
+	pr_err("[DEBUG]%s: UFS SHUTDOWN START\n", __func__);
+
+	usleep_range(10000000, 11000000);
+
 	if (!hba->is_powered)
 		goto out;
 
@@ -8294,6 +8299,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 	if (ret)
 		dev_err(hba->dev, "%s failed, err %d\n", __func__, ret);
 	/* allow force shutdown even in case of errors */
+	pr_err("[DEBUG]%s: UFS SHUTDOWN END\n", __func__);
 	return 0;
 }
 EXPORT_SYMBOL(ufshcd_shutdown);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 6ffc08a..3a40d94 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -677,6 +677,7 @@ struct ufs_hba {
 	u16 ee_ctrl_mask;
 	u16 hba_enable_delay_us;
 	bool is_powered;
+	bool shutting_down;
 
 	/* Work Queues */
 	struct work_struct eh_work;
-- 
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