From 436f6d0005d69becb70559c106eda744b096cdde Mon Sep 17 00:00:00 2001 From: Alexey Makhalov Date: Mon, 20 Dec 2021 11:05:14 -0800 Subject: [PATCH] scsi: vmw_pvscsi: Set residual data length conditionally commit 142c779d05d1fef75134c3cb63f52ccbc96d9e1f upstream. The PVSCSI implementation in the VMware hypervisor under specific configuration ("SCSI Bus Sharing" set to "Physical") returns zero dataLen in the completion descriptor for READ CAPACITY(16). As a result, the kernel can not detect proper disk geometry. This can be recognized by the kernel message: [ 0.776588] sd 1:0:0:0: [sdb] Sector size 0 reported, assuming 512. The PVSCSI implementation in QEMU does not set dataLen at all, keeping it zeroed. This leads to a boot hang as was reported by Shmulik Ladkani. It is likely that the controller returns the garbage at the end of the buffer. Residual length should be set by the driver in that case. The SCSI layer will erase corresponding data. See commit bdb2b8cab439 ("[SCSI] erase invalid data returned by device") for details. Commit e662502b3a78 ("scsi: vmw_pvscsi: Set correct residual data length") introduced the issue by setting residual length unconditionally, causing the SCSI layer to erase the useful payload beyond dataLen when this value is returned as 0. As a result, considering existing issues in implementations of PVSCSI controllers, we do not want to call scsi_set_resid() when dataLen == 0. Calling scsi_set_resid() has no effect if dataLen equals buffer length. Link: https://lore.kernel.org/lkml/20210824120028.30d9c071@blondie/ Link: https://lore.kernel.org/r/20211220190514.55935-1-amakhalov@vmware.com Fixes: e662502b3a78 ("scsi: vmw_pvscsi: Set correct residual data length") Cc: Matt Wang Cc: Martin K. Petersen Cc: Vishal Bhakta Cc: VMware PV-Drivers Cc: James E.J. Bottomley Cc: linux-scsi@vger.kernel.org Cc: stable@vger.kernel.org Reported-and-suggested-by: Shmulik Ladkani Signed-off-by: Alexey Makhalov Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/vmw_pvscsi.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c index 0ac342b1deb9..0370ff6dd2ef 100644 --- a/drivers/scsi/vmw_pvscsi.c +++ b/drivers/scsi/vmw_pvscsi.c @@ -578,9 +578,12 @@ static void pvscsi_complete_request(struct pvscsi_adapter *adapter, * Commands like INQUIRY may transfer less data than * requested by the initiator via bufflen. Set residual * count to make upper layer aware of the actual amount - * of data returned. + * of data returned. There are cases when controller + * returns zero dataLen with non zero data - do not set + * residual count in that case. */ - scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen); + if (e->dataLen && (e->dataLen < scsi_bufflen(cmd))) + scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen); cmd->result = (DID_OK << 16); break;