On 7/10/2025 9:41 PM, Greg KH wrote:

On Wed, Jul 02, 2025 at 08:29:45AM +0000, Xinyu Zheng wrote:

quoted

From: Dongli Zhang <redacted>

[ Upstream commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 ]

The vhost-scsi completion path may access vq->log_base when vq->log_used is
already set to false.

     vhost-thread                       QEMU-thread

vhost_scsi_complete_cmd_work()
-> vhost_add_used()
    -> vhost_add_used_n()
       if (unlikely(vq->log_used))
                                       QEMU disables vq->log_used
                                       via VHOST_SET_VRING_ADDR.
                                       mutex_lock(&vq->mutex);
                                       vq->log_used = false now!
                                       mutex_unlock(&vq->mutex);

				      QEMU gfree(vq->log_base)
         log_used()
         -> log_write(vq->log_base)

Assuming the VMM is QEMU. The vq->log_base is from QEMU userpace and can be
reclaimed via gfree(). As a result, this causes invalid memory writes to
QEMU userspace.

The control queue path has the same issue.

CVE-2025-38074

This is not needed.

quoted

Cc: stable@vger.kernel.org#5.10.x

What about 5.15.y and 6.1.y?  We can't take a patch just for 5.10 as
that would cause regressions, right?

Please provide all relevant backports and I will be glad to queue them
up then.  I'll drop this from my queue for now, thanks.

greg k-h

Sorry for forgetting the 5.15.y and 6.1.y patches. I will resend it as 
soon as possible. Thanks for pointing out my patch format error.

Xinyu Zheng