[2/2] libnvdimm/security: ensure sysfs poll thread woke up and fetch updated attr
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Message ID 1595606959-8516-2-git-send-email-jane.chu@oracle.com
State New
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Series
  • [1/2] libnvdimm/security: 'security' attr never show 'overwrite' state
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Commit Message

Jane Chu July 24, 2020, 4:09 p.m. UTC
commit 7d988097c546 ("acpi/nfit, libnvdimm/security: Add security DSM overwrite support")
adds a sysfs_notify_dirent() to wake up userspace poll thread when the "overwrite"
operation has completed. But the notification is issued before the internal
dimm security state and flags have been updated, so the userspace poll thread
wakes up and fetches the not-yet-updated attr and falls back to sleep, forever.
But if user from another terminal issue "ndctl wait-overwrite nmemX" again,
the command returns instantly.

Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Fixes: 7d988097c546 ("acpi/nfit, libnvdimm/security: Add security DSM overwrite support")
Signed-off-by: Jane Chu <jane.chu@oracle.com>
---
 drivers/nvdimm/security.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Comments

Dave Jiang Aug. 3, 2020, 8:42 p.m. UTC | #1
On 7/24/2020 9:09 AM, Jane Chu wrote:
> commit 7d988097c546 ("acpi/nfit, libnvdimm/security: Add security DSM overwrite support")
> adds a sysfs_notify_dirent() to wake up userspace poll thread when the "overwrite"
> operation has completed. But the notification is issued before the internal
> dimm security state and flags have been updated, so the userspace poll thread
> wakes up and fetches the not-yet-updated attr and falls back to sleep, forever.
> But if user from another terminal issue "ndctl wait-overwrite nmemX" again,
> the command returns instantly.
> 
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Fixes: 7d988097c546 ("acpi/nfit, libnvdimm/security: Add security DSM overwrite support")
> Signed-off-by: Jane Chu <jane.chu@oracle.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>   drivers/nvdimm/security.c | 11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
> index 8f3971c..4b80150 100644
> --- a/drivers/nvdimm/security.c
> +++ b/drivers/nvdimm/security.c
> @@ -450,14 +450,19 @@ void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
>   	else
>   		dev_dbg(&nvdimm->dev, "overwrite completed\n");
>   
> -	if (nvdimm->sec.overwrite_state)
> -		sysfs_notify_dirent(nvdimm->sec.overwrite_state);
> +	/*
> +	 * Mark the overwrite work done and update dimm security flags,
> +	 * then send a sysfs event notification to wake up userspace
> +	 * poll threads to picked up the changed state.
> +	 */
>   	nvdimm->sec.overwrite_tmo = 0;
>   	clear_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
>   	clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
> -	put_device(&nvdimm->dev);
>   	nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
>   	nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
> +	if (nvdimm->sec.overwrite_state)
> +		sysfs_notify_dirent(nvdimm->sec.overwrite_state);
> +	put_device(&nvdimm->dev);
>   }
>   
>   void nvdimm_security_overwrite_query(struct work_struct *work)
>

Patch
diff mbox series

diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
index 8f3971c..4b80150 100644
--- a/drivers/nvdimm/security.c
+++ b/drivers/nvdimm/security.c
@@ -450,14 +450,19 @@  void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
 	else
 		dev_dbg(&nvdimm->dev, "overwrite completed\n");
 
-	if (nvdimm->sec.overwrite_state)
-		sysfs_notify_dirent(nvdimm->sec.overwrite_state);
+	/*
+	 * Mark the overwrite work done and update dimm security flags,
+	 * then send a sysfs event notification to wake up userspace
+	 * poll threads to picked up the changed state.
+	 */
 	nvdimm->sec.overwrite_tmo = 0;
 	clear_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
 	clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
-	put_device(&nvdimm->dev);
 	nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
 	nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
+	if (nvdimm->sec.overwrite_state)
+		sysfs_notify_dirent(nvdimm->sec.overwrite_state);
+	put_device(&nvdimm->dev);
 }
 
 void nvdimm_security_overwrite_query(struct work_struct *work)