This is a note to let you know that I've just added the patch titled
vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vhost-scsi-fix-incorrect-usage-of-get_user_pages_fast-write-parameter.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 60a01f558af9c48b0bb31f303c479e32721add3f Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <[email protected]>
Date: Fri, 25 Oct 2013 10:44:15 -0700
Subject: vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter
From: Nicholas Bellinger <[email protected]>
commit 60a01f558af9c48b0bb31f303c479e32721add3f upstream.
This patch addresses a long-standing bug where the get_user_pages_fast()
write parameter used for setting the underlying page table entry permission
bits was incorrectly set to write=1 for data_direction=DMA_TO_DEVICE, and
passed into get_user_pages_fast() via vhost_scsi_map_iov_to_sgl().
However, this parameter is intended to signal WRITEs to pinned userspace
PTEs for the virtio-scsi DMA_FROM_DEVICE -> READ payload case, and *not*
for the virtio-scsi DMA_TO_DEVICE -> WRITE payload case.
This bug would manifest itself as random process segmentation faults on
KVM host after repeated vhost starts + stops and/or with lots of vhost
endpoints + LUNs.
Cc: Stefan Hajnoczi <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Cc: Asias He <[email protected]>
Signed-off-by: Nicholas Bellinger <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/vhost/scsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1017,7 +1017,7 @@ static void vhost_scsi_handle_vq(struct
if (data_direction != DMA_NONE) {
ret = vhost_scsi_map_iov_to_sgl(tv_cmd,
&vq->iov[data_first], data_num,
- data_direction == DMA_TO_DEVICE);
+ data_direction == DMA_FROM_DEVICE);
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to sgl\n");
goto err_free;
Patches currently in stable-queue which might be from [email protected] are
queue-3.10/target-pscsi-fix-return-value-check.patch
queue-3.10/vhost-scsi-fix-incorrect-usage-of-get_user_pages_fast-write-parameter.patch
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