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| author | Michael Kelley <mikelley@microsoft.com> | 2022-12-04 20:52:44 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2022-12-14 03:54:44 +0100 |
| commit | 67ff3d0a49f3d445c3922e30a54e03c161da561e (patch) | |
| tree | 445c362121cd8ec2187901f566a3186a0a4f8b17 /drivers/scsi/storvsc_drv.c | |
| parent | scsi: iscsi: Fix multiple iSCSI session unbind events sent to userspace (diff) | |
| download | linux-67ff3d0a49f3d445c3922e30a54e03c161da561e.tar.xz linux-67ff3d0a49f3d445c3922e30a54e03c161da561e.zip | |
scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM
storvsc_queuecommand() maps the scatter/gather list using scsi_dma_map(),
which in a confidential VM allocates swiotlb bounce buffers. If the I/O
submission fails in storvsc_do_io(), the I/O is typically retried by higher
level code, but the bounce buffer memory is never freed. The mostly like
cause of I/O submission failure is a full VMBus channel ring buffer, which
is not uncommon under high I/O loads. Eventually enough bounce buffer
memory leaks that the confidential VM can't do any I/O. The same problem
can arise in a non-confidential VM with kernel boot parameter
swiotlb=force.
Fix this by doing scsi_dma_unmap() in the case of an I/O submission
error, which frees the bounce buffer memory.
Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1670183564-76254-1-git-send-email-mikelley@microsoft.com
Tested-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/storvsc_drv.c')
| -rw-r--r-- | drivers/scsi/storvsc_drv.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index a84194d82347..0252ee2dd844 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -1824,6 +1824,9 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) ret = storvsc_do_io(dev, cmd_request, get_cpu()); put_cpu(); + if (ret) + scsi_dma_unmap(scmnd); + if (ret == -EAGAIN) { /* no more space */ ret = SCSI_MLQUEUE_DEVICE_BUSY; |