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* [PATCH v4 1/2] scsi: ufs: Fix a possible NULL pointer issue
       [not found] <1610546230-14732-1-git-send-email-cang@codeaurora.org>
@ 2021-01-13 13:57 ` Can Guo
  2021-01-13 13:57 ` [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs Can Guo
  1 sibling, 0 replies; 4+ messages in thread
From: Can Guo @ 2021-01-13 13:57 UTC (permalink / raw)
  To: asutoshd, nguyenb, hongwus, rnayak, linux-scsi, kernel-team,
	saravanak, salyzyn, cang
  Cc: Martin K. Petersen, James E.J. Bottomley, open list, Avri Altman,
	moderated list:ARM/Mediatek SoC support, Alim Akhtar,
	Matthias Brugger, Stanley Chu,
	moderated list:ARM/Mediatek SoC support, Bean Huo

During system resume/suspend, hba could be NULL. In this case, do not touch
eh_sem.

Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM events and async scan")

Acked-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 53fd59c..969aed9 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -94,6 +94,8 @@
 		       16, 4, buf, __len, false);                        \
 } while (0)
 
+static bool early_suspend;
+
 int ufshcd_dump_regs(struct ufs_hba *hba, size_t offset, size_t len,
 		     const char *prefix)
 {
@@ -8953,8 +8955,14 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	int ret = 0;
 	ktime_t start = ktime_get();
 
+	if (!hba) {
+		early_suspend = true;
+		return 0;
+	}
+
 	down(&hba->eh_sem);
-	if (!hba || !hba->is_powered)
+
+	if (!hba->is_powered)
 		return 0;
 
 	if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) ==
@@ -9002,9 +9010,12 @@ int ufshcd_system_resume(struct ufs_hba *hba)
 	int ret = 0;
 	ktime_t start = ktime_get();
 
-	if (!hba) {
-		up(&hba->eh_sem);
+	if (!hba)
 		return -EINVAL;
+
+	if (unlikely(early_suspend)) {
+		early_suspend = false;
+		down(&hba->eh_sem);
 	}
 
 	if (!hba->is_powered || pm_runtime_suspended(hba->dev))
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.


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http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs
       [not found] <1610546230-14732-1-git-send-email-cang@codeaurora.org>
  2021-01-13 13:57 ` [PATCH v4 1/2] scsi: ufs: Fix a possible NULL pointer issue Can Guo
@ 2021-01-13 13:57 ` Can Guo
  2021-01-13 14:53   ` Adrian Hunter
  1 sibling, 1 reply; 4+ messages in thread
From: Can Guo @ 2021-01-13 13:57 UTC (permalink / raw)
  To: asutoshd, nguyenb, hongwus, rnayak, linux-scsi, kernel-team,
	saravanak, salyzyn, cang
  Cc: Martin K. Petersen, Nitin Rawat, open list, James E.J. Bottomley,
	Adrian Hunter, Satya Tangirala, Avri Altman,
	moderated list:ARM/Mediatek SoC support, Alim Akhtar,
	Matthias Brugger, Stanley Chu,
	moderated list:ARM/Mediatek SoC support, Bean Huo

User layer may access sysfs nodes when system PM ops or error handling
is running, which can cause various problems. Rename eh_sem to host_sem
and use it to protect PM ops and error handling from user layer intervene.

Acked-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufs-sysfs.c | 106 ++++++++++++++++++++++++++++++++++++-------
 drivers/scsi/ufs/ufshcd.c    |  42 ++++++++++-------
 drivers/scsi/ufs/ufshcd.h    |  10 +++-
 3 files changed, 125 insertions(+), 33 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 0e14384..7cafffc 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -154,18 +154,29 @@ static ssize_t auto_hibern8_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
 	u32 ahit;
+	int ret;
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 
 	if (!ufshcd_is_auto_hibern8_supported(hba))
 		return -EOPNOTSUPP;
 
+	down(&hba->host_sem);
+	if (!ufshcd_is_sysfs_allowed(hba)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
 	pm_runtime_get_sync(hba->dev);
 	ufshcd_hold(hba, false);
 	ahit = ufshcd_readl(hba, REG_AUTO_HIBERNATE_IDLE_TIMER);
 	ufshcd_release(hba);
 	pm_runtime_put_sync(hba->dev);
 
-	return sysfs_emit(buf, "%d\n", ufshcd_ahit_to_us(ahit));
+	ret = sysfs_emit(buf, "%d\n", ufshcd_ahit_to_us(ahit));
+
+out:
+	up(&hba->host_sem);
+	return ret;
 }
 
 static ssize_t auto_hibern8_store(struct device *dev,
@@ -174,6 +185,7 @@ static ssize_t auto_hibern8_store(struct device *dev,
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 	unsigned int timer;
+	int ret = 0;
 
 	if (!ufshcd_is_auto_hibern8_supported(hba))
 		return -EOPNOTSUPP;
@@ -184,9 +196,17 @@ static ssize_t auto_hibern8_store(struct device *dev,
 	if (timer > UFSHCI_AHIBERN8_MAX)
 		return -EINVAL;
 
+	down(&hba->host_sem);
+	if (!ufshcd_is_sysfs_allowed(hba)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
 	ufshcd_auto_hibern8_update(hba, ufshcd_us_to_ahit(timer));
 
-	return count;
+out:
+	up(&hba->host_sem);
+	return ret ? ret : count;
 }
 
 static DEVICE_ATTR_RW(rpm_lvl);
@@ -225,12 +245,21 @@ static ssize_t ufs_sysfs_read_desc_param(struct ufs_hba *hba,
 	if (param_size > 8)
 		return -EINVAL;
 
+	down(&hba->host_sem);
+	if (!ufshcd_is_sysfs_allowed(hba)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
 	pm_runtime_get_sync(hba->dev);
 	ret = ufshcd_read_desc_param(hba, desc_id, desc_index,
 				param_offset, desc_buf, param_size);
 	pm_runtime_put_sync(hba->dev);
-	if (ret)
-		return -EINVAL;
+	if (ret) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	switch (param_size) {
 	case 1:
 		ret = sysfs_emit(sysfs_buf, "0x%02X\n", *desc_buf);
@@ -249,6 +278,8 @@ static ssize_t ufs_sysfs_read_desc_param(struct ufs_hba *hba,
 		break;
 	}
 
+out:
+	up(&hba->host_sem);
 	return ret;
 }
 
@@ -591,9 +622,16 @@ static ssize_t _name##_show(struct device *dev,				\
 	int desc_len = QUERY_DESC_MAX_SIZE;				\
 	u8 *desc_buf;							\
 									\
+	down(&hba->host_sem);						\
+	if (!ufshcd_is_sysfs_allowed(hba)) {				\
+		up(&hba->host_sem);					\
+		return -EBUSY;						\
+	}								\
 	desc_buf = kzalloc(QUERY_DESC_MAX_SIZE, GFP_ATOMIC);		\
-	if (!desc_buf)                                                  \
-		return -ENOMEM;                                         \
+	if (!desc_buf) {						\
+		up(&hba->host_sem);					\
+		return -ENOMEM;						\
+	}								\
 	pm_runtime_get_sync(hba->dev);					\
 	ret = ufshcd_query_descriptor_retry(hba,			\
 		UPIU_QUERY_OPCODE_READ_DESC, QUERY_DESC_IDN_DEVICE,	\
@@ -609,10 +647,11 @@ static ssize_t _name##_show(struct device *dev,				\
 				      SD_ASCII_STD);			\
 	if (ret < 0)							\
 		goto out;						\
-	ret = sysfs_emit(buf, "%s\n", desc_buf);		\
+	ret = sysfs_emit(buf, "%s\n", desc_buf);			\
 out:									\
 	pm_runtime_put_sync(hba->dev);					\
 	kfree(desc_buf);						\
+	up(&hba->host_sem);						\
 	return ret;							\
 }									\
 static DEVICE_ATTR_RO(_name)
@@ -651,15 +690,26 @@ static ssize_t _name##_show(struct device *dev,				\
 	u8 index = 0;							\
 	int ret;							\
 	struct ufs_hba *hba = dev_get_drvdata(dev);			\
+									\
+	down(&hba->host_sem);						\
+	if (!ufshcd_is_sysfs_allowed(hba)) {				\
+		up(&hba->host_sem);					\
+		return -EBUSY;						\
+	}								\
 	if (ufshcd_is_wb_flags(QUERY_FLAG_IDN##_uname))			\
 		index = ufshcd_wb_get_query_index(hba);			\
 	pm_runtime_get_sync(hba->dev);					\
 	ret = ufshcd_query_flag(hba, UPIU_QUERY_OPCODE_READ_FLAG,	\
 		QUERY_FLAG_IDN##_uname, index, &flag);			\
 	pm_runtime_put_sync(hba->dev);					\
-	if (ret)							\
-		return -EINVAL;						\
-	return sysfs_emit(buf, "%s\n", flag ? "true" : "false");	\
+	if (ret) {							\
+		ret = -EINVAL;						\
+		goto out;						\
+	}								\
+	ret = sysfs_emit(buf, "%s\n", flag ? "true" : "false");		\
+out:									\
+	up(&hba->host_sem);						\
+	return ret;							\
 }									\
 static DEVICE_ATTR_RO(_name)
 
@@ -709,15 +759,26 @@ static ssize_t _name##_show(struct device *dev,				\
 	u32 value;							\
 	int ret;							\
 	u8 index = 0;							\
+									\
+	down(&hba->host_sem);						\
+	if (!ufshcd_is_sysfs_allowed(hba)) {				\
+		up(&hba->host_sem);					\
+		return -EBUSY;						\
+	}								\
 	if (ufshcd_is_wb_attrs(QUERY_ATTR_IDN##_uname))			\
 		index = ufshcd_wb_get_query_index(hba);			\
 	pm_runtime_get_sync(hba->dev);					\
 	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,	\
 		QUERY_ATTR_IDN##_uname, index, 0, &value);		\
 	pm_runtime_put_sync(hba->dev);					\
-	if (ret)							\
-		return -EINVAL;						\
-	return sysfs_emit(buf, "0x%08X\n", value);			\
+	if (ret) {							\
+		ret = -EINVAL;						\
+		goto out;						\
+	}								\
+	ret = sysfs_emit(buf, "0x%08X\n", value);			\
+out:									\
+	up(&hba->host_sem);						\
+	return ret;							\
 }									\
 static DEVICE_ATTR_RO(_name)
 
@@ -850,13 +911,26 @@ static ssize_t dyn_cap_needed_attribute_show(struct device *dev,
 	u8 lun = ufshcd_scsi_to_upiu_lun(sdev->lun);
 	int ret;
 
+	down(&hba->host_sem);
+	if (!ufshcd_is_sysfs_allowed(hba)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
 	pm_runtime_get_sync(hba->dev);
 	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
 		QUERY_ATTR_IDN_DYN_CAP_NEEDED, lun, 0, &value);
 	pm_runtime_put_sync(hba->dev);
-	if (ret)
-		return -EINVAL;
-	return sysfs_emit(buf, "0x%08X\n", value);
+	if (ret) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = sysfs_emit(buf, "0x%08X\n", value);
+
+out:
+	up(&hba->host_sem);
+	return ret;
 }
 static DEVICE_ATTR_RO(dyn_cap_needed_attribute);
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 969aed9..d2bdf0c 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1551,11 +1551,17 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 	u32 value;
-	int err;
+	int err = 0;
 
 	if (kstrtou32(buf, 0, &value))
 		return -EINVAL;
 
+	down(&hba->host_sem);
+	if (!ufshcd_is_sysfs_allowed(hba)) {
+		err = -EBUSY;
+		goto out;
+	}
+
 	value = !!value;
 	if (value == hba->clk_scaling.is_allowed)
 		goto out;
@@ -1581,7 +1587,8 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	ufshcd_release(hba);
 	pm_runtime_put_sync(hba->dev);
 out:
-	return count;
+	up(&hba->host_sem);
+	return err ? err : count;
 }
 
 static void ufshcd_clkscaling_init_sysfs(struct ufs_hba *hba)
@@ -5779,9 +5786,10 @@ static void ufshcd_err_handling_unprepare(struct ufs_hba *hba)
 
 static inline bool ufshcd_err_handling_should_stop(struct ufs_hba *hba)
 {
-	return (!hba->is_powered || hba->ufshcd_state == UFSHCD_STATE_ERROR ||
+	return (!hba->is_powered || hba->shutting_down ||
+		hba->ufshcd_state == UFSHCD_STATE_ERROR ||
 		(!(hba->saved_err || hba->saved_uic_err || hba->force_reset ||
-			ufshcd_is_link_broken(hba))));
+		   ufshcd_is_link_broken(hba))));
 }
 
 #ifdef CONFIG_PM
@@ -5851,13 +5859,13 @@ static void ufshcd_err_handler(struct work_struct *work)
 
 	hba = container_of(work, struct ufs_hba, eh_work);
 
-	down(&hba->eh_sem);
+	down(&hba->host_sem);
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	if (ufshcd_err_handling_should_stop(hba)) {
 		if (hba->ufshcd_state != UFSHCD_STATE_ERROR)
 			hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
 		spin_unlock_irqrestore(hba->host->host_lock, flags);
-		up(&hba->eh_sem);
+		up(&hba->host_sem);
 		return;
 	}
 	ufshcd_set_eh_in_progress(hba);
@@ -6026,7 +6034,7 @@ static void ufshcd_err_handler(struct work_struct *work)
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	ufshcd_scsi_unblock_requests(hba);
 	ufshcd_err_handling_unprepare(hba);
-	up(&hba->eh_sem);
+	up(&hba->host_sem);
 }
 
 /**
@@ -7928,10 +7936,10 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
 	struct ufs_hba *hba = (struct ufs_hba *)data;
 	int ret;
 
-	down(&hba->eh_sem);
+	down(&hba->host_sem);
 	/* Initialize hba, detect and initialize UFS device */
 	ret = ufshcd_probe_hba(hba, true);
-	up(&hba->eh_sem);
+	up(&hba->host_sem);
 	if (ret)
 		goto out;
 
@@ -8960,7 +8968,7 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 		return 0;
 	}
 
-	down(&hba->eh_sem);
+	down(&hba->host_sem);
 
 	if (!hba->is_powered)
 		return 0;
@@ -8993,7 +9001,7 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	if (!ret)
 		hba->is_sys_suspended = true;
 	else
-		up(&hba->eh_sem);
+		up(&hba->host_sem);
 	return ret;
 }
 EXPORT_SYMBOL(ufshcd_system_suspend);
@@ -9015,7 +9023,7 @@ int ufshcd_system_resume(struct ufs_hba *hba)
 
 	if (unlikely(early_suspend)) {
 		early_suspend = false;
-		down(&hba->eh_sem);
+		down(&hba->host_sem);
 	}
 
 	if (!hba->is_powered || pm_runtime_suspended(hba->dev))
@@ -9032,7 +9040,7 @@ int ufshcd_system_resume(struct ufs_hba *hba)
 		hba->curr_dev_pwr_mode, hba->uic_link_state);
 	if (!ret)
 		hba->is_sys_suspended = false;
-	up(&hba->eh_sem);
+	up(&hba->host_sem);
 	return ret;
 }
 EXPORT_SYMBOL(ufshcd_system_resume);
@@ -9124,7 +9132,10 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 {
 	int ret = 0;
 
-	down(&hba->eh_sem);
+	down(&hba->host_sem);
+	hba->shutting_down = true;
+	up(&hba->host_sem);
+
 	if (!hba->is_powered)
 		goto out;
 
@@ -9138,7 +9149,6 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 	if (ret)
 		dev_err(hba->dev, "%s failed, err %d\n", __func__, ret);
 	hba->is_powered = false;
-	up(&hba->eh_sem);
 	/* allow force shutdown even in case of errors */
 	return 0;
 }
@@ -9334,7 +9344,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	INIT_WORK(&hba->eh_work, ufshcd_err_handler);
 	INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);
 
-	sema_init(&hba->eh_sem, 1);
+	sema_init(&hba->host_sem, 1);
 
 	/* Initialize UIC command mutex */
 	mutex_init(&hba->uic_cmd_mutex);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 85f9d0f..9dfd9c3 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -663,6 +663,8 @@ struct ufs_hba_variant_params {
  * @intr_mask: Interrupt Mask Bits
  * @ee_ctrl_mask: Exception event control mask
  * @is_powered: flag to check if HBA is powered
+ * @shutting_down: flag to check if shutdown has been invoked
+ * @host_sem: semaphore used to serialize concurrent contexts
  * @eh_wq: Workqueue that eh_work works on
  * @eh_work: Worker to handle UFS errors that require s/w attention
  * @eeh_work: Worker to handle exception events
@@ -759,7 +761,8 @@ struct ufs_hba {
 	u32 intr_mask;
 	u16 ee_ctrl_mask;
 	bool is_powered;
-	struct semaphore eh_sem;
+	bool shutting_down;
+	struct semaphore host_sem;
 
 	/* Work Queues */
 	struct workqueue_struct *eh_wq;
@@ -883,6 +886,11 @@ static inline bool ufshcd_is_wb_allowed(struct ufs_hba *hba)
 	return hba->caps & UFSHCD_CAP_WB_EN;
 }
 
+static inline bool ufshcd_is_sysfs_allowed(struct ufs_hba *hba)
+{
+	return !hba->shutting_down;
+}
+
 #define ufshcd_writel(hba, val, reg)	\
 	writel((val), (hba)->mmio_base + (reg))
 #define ufshcd_readl(hba, reg)	\
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.


_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs
  2021-01-13 13:57 ` [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs Can Guo
@ 2021-01-13 14:53   ` Adrian Hunter
  2021-01-14  0:48     ` Can Guo
  0 siblings, 1 reply; 4+ messages in thread
From: Adrian Hunter @ 2021-01-13 14:53 UTC (permalink / raw)
  To: Can Guo, asutoshd, nguyenb, hongwus, rnayak, linux-scsi,
	kernel-team, saravanak, salyzyn
  Cc: Martin K. Petersen, Nitin Rawat, James E.J. Bottomley, open list,
	Satya Tangirala, Avri Altman,
	moderated list:ARM/Mediatek SoC support, Alim Akhtar,
	Matthias Brugger, Stanley Chu,
	moderated list:ARM/Mediatek SoC support, Bean Huo

On 13/01/21 3:57 pm, Can Guo wrote:
> User layer may access sysfs nodes when system PM ops or error handling
> is running, which can cause various problems. Rename eh_sem to host_sem
> and use it to protect PM ops and error handling from user layer intervene.
> 
> Acked-by: Avri Altman <avri.altman@wdc.com>
> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
>  drivers/scsi/ufs/ufs-sysfs.c | 106 ++++++++++++++++++++++++++++++++++++-------
>  drivers/scsi/ufs/ufshcd.c    |  42 ++++++++++-------
>  drivers/scsi/ufs/ufshcd.h    |  10 +++-
>  3 files changed, 125 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
> index 0e14384..7cafffc 100644
> --- a/drivers/scsi/ufs/ufs-sysfs.c
> +++ b/drivers/scsi/ufs/ufs-sysfs.c
> @@ -154,18 +154,29 @@ static ssize_t auto_hibern8_show(struct device *dev,
>  				 struct device_attribute *attr, char *buf)
>  {
>  	u32 ahit;
> +	int ret;
>  	struct ufs_hba *hba = dev_get_drvdata(dev);
>  
>  	if (!ufshcd_is_auto_hibern8_supported(hba))
>  		return -EOPNOTSUPP;
>  
> +	down(&hba->host_sem);
> +	if (!ufshcd_is_sysfs_allowed(hba)) {

I expect debugfs has the same potential problem, so maybe
ufshcd_is_sysfs_allowed() is not quite the right name.

> +		ret = -EBUSY;
> +		goto out;
> +	}
> +

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^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs
  2021-01-13 14:53   ` Adrian Hunter
@ 2021-01-14  0:48     ` Can Guo
  0 siblings, 0 replies; 4+ messages in thread
From: Can Guo @ 2021-01-14  0:48 UTC (permalink / raw)
  To: Adrian Hunter
  Cc: moderated list:ARM/Mediatek SoC support, Bean Huo, rnayak,
	saravanak, linux-scsi, Nitin Rawat, open list,
	James E.J. Bottomley, nguyenb, Satya Tangirala, Avri Altman,
	moderated list:ARM/Mediatek SoC support, salyzyn, Alim Akhtar,
	Martin K. Petersen, Matthias Brugger, Stanley Chu, kernel-team,
	hongwus, asutoshd

On 2021-01-13 22:53, Adrian Hunter wrote:
> On 13/01/21 3:57 pm, Can Guo wrote:
>> User layer may access sysfs nodes when system PM ops or error handling
>> is running, which can cause various problems. Rename eh_sem to 
>> host_sem
>> and use it to protect PM ops and error handling from user layer 
>> intervene.
>> 
>> Acked-by: Avri Altman <avri.altman@wdc.com>
>> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>>  drivers/scsi/ufs/ufs-sysfs.c | 106 
>> ++++++++++++++++++++++++++++++++++++-------
>>  drivers/scsi/ufs/ufshcd.c    |  42 ++++++++++-------
>>  drivers/scsi/ufs/ufshcd.h    |  10 +++-
>>  3 files changed, 125 insertions(+), 33 deletions(-)
>> 
>> diff --git a/drivers/scsi/ufs/ufs-sysfs.c 
>> b/drivers/scsi/ufs/ufs-sysfs.c
>> index 0e14384..7cafffc 100644
>> --- a/drivers/scsi/ufs/ufs-sysfs.c
>> +++ b/drivers/scsi/ufs/ufs-sysfs.c
>> @@ -154,18 +154,29 @@ static ssize_t auto_hibern8_show(struct device 
>> *dev,
>>  				 struct device_attribute *attr, char *buf)
>>  {
>>  	u32 ahit;
>> +	int ret;
>>  	struct ufs_hba *hba = dev_get_drvdata(dev);
>> 
>>  	if (!ufshcd_is_auto_hibern8_supported(hba))
>>  		return -EOPNOTSUPP;
>> 
>> +	down(&hba->host_sem);
>> +	if (!ufshcd_is_sysfs_allowed(hba)) {
> 
> I expect debugfs has the same potential problem, so maybe
> ufshcd_is_sysfs_allowed() is not quite the right name.

I noticed your debugfs change - currently it is only printing
error counts recorded in hba struct, which is fine.
Even in this patch, the check is only added for those entries
which need to talk with HW. Sysfs nodes like show/store rpm/spm_lvl
does not need this check.

Thanks,
Can Guo.

> 
>> +		ret = -EBUSY;
>> +		goto out;
>> +	}
>> +

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^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-01-14  0:48 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-01-13 13:57 ` [PATCH v4 1/2] scsi: ufs: Fix a possible NULL pointer issue Can Guo
2021-01-13 13:57 ` [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs Can Guo
2021-01-13 14:53   ` Adrian Hunter
2021-01-14  0:48     ` Can Guo

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