[PATCH] Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()"

[PATCH] Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()"

[Andrea Parri (Microsoft)]

This reverts commit 3b8c72d076c42bf27284cda7b2b2b522810686f8.

Dexuan reported a regression where StorVSC fails to probe a device (and
where, consequently, the VM may fail to boot).  The root-cause analysis
led to a long-standing race condition that is exposed by the validation
/commit in question.  Let's put the new validation aside until a proper
solution for that race condition is in place.

Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
---
 drivers/scsi/storvsc_drv.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 99c8ff81de746..ded00a89bfc4e 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1246,11 +1246,6 @@ static void storvsc_on_channel_callback(void *context)
 		request = (struct storvsc_cmd_request *)
 			((unsigned long)desc->trans_id);
 
-		if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) - vmscsi_size_delta) {
-			dev_err(&device->device, "Invalid packet len\n");
-			continue;
-		}
-
 		if (request == &stor_device->init_request ||
 		    request == &stor_device->reset_request) {
 			memcpy(&request->vstor_packet, packet,
-- 
2.25.1

Re: [PATCH] Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()"

[Wei Liu]

On Fri, Dec 11, 2020 at 02:14:04PM +0100, Andrea Parri (Microsoft) wrote:
> This reverts commit 3b8c72d076c42bf27284cda7b2b2b522810686f8.
> 
> Dexuan reported a regression where StorVSC fails to probe a device (and
> where, consequently, the VM may fail to boot).  The root-cause analysis
> led to a long-standing race condition that is exposed by the validation
> /commit in question.  Let's put the new validation aside until a proper
> solution for that race condition is in place.
> 
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
> Cc: Dexuan Cui <decui@microsoft.com>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: linux-scsi@vger.kernel.org

Hi Martin

Sorry for the last minute patch. We would very like this goes into 5.10
if possible; otherwise Linux 5.10 is going to be broken on Hyper-V.  :-(

Wei.

Re: [PATCH] Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()"

[Martin K. Petersen]

Wei,

> Sorry for the last minute patch. We would very like this goes into
> 5.10 if possible; otherwise Linux 5.10 is going to be broken on
> Hyper-V.  :-(

Applied to 5.10/scsi-fixes.

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH] Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()"

[Wei Liu]

On Fri, Dec 11, 2020 at 09:59:34AM -0500, Martin K. Petersen wrote:
> 
> Wei,
> 
> > Sorry for the last minute patch. We would very like this goes into
> > 5.10 if possible; otherwise Linux 5.10 is going to be broken on
> > Hyper-V.  :-(
> 
> Applied to 5.10/scsi-fixes.

Thanks Martin.