# CVE-2022-50738: CVE-2022-50738

Status: published. Published: 2025-12-24. Updated: 2026-11-10.

In the Linux kernel, the following vulnerability has been resolved:

vhost-vdpa: fix an iotlb memory leak

Before commit 3d5698793897 ("vhost-vdpa: introduce asid based IOTLB")
we called vhost_vdpa_iotlb_unmap(v, iotlb, 0ULL, 0ULL - 1) during
release to free all the resources allocated when processing user IOTLB
messages through vhost_vdpa_process_iotlb_update().
That commit changed the handling of IOTLB a bit, and we accidentally
removed some code called during the release.

We partially fixed this with commit 037d4305569a ("vhost-vdpa: call
vhost_vdpa_cleanup during the release") but a potential memory leak is
still there as showed by kmemleak if the application does not send
VHOST_IOTLB_INVALIDATE or crashes:

  unreferenced object 0xffff888007fbaa30 (size 16):
    comm "blkio-bench", pid 914, jiffies 4294993521 (age 885.500s)
    hex dump (first 16 bytes):
      40 73 41 07 80 88 ff ff 00 00 00 00 00 00 00 00  @sA.............
    backtrace:
      [<0000000087736d2a>] kmem_cache_alloc_trace+0x142/0x1c0
      [<0000000060740f50>] vhost_vdpa_process_iotlb_msg+0x68c/0x901 [vhost_vdpa]
      [<0000000083e8e205>] vhost_chr_write_iter+0xc0/0x4a0 [vhost]
      [<000000008f2f414a>] vhost_vdpa_chr_write_iter+0x18/0x20 [vhost_vdpa]
      [<00000000de1cd4a0>] vfs_write+0x216/0x4b0
      [<00000000a2850200>] ksys_write+0x71/0xf0
      [<00000000de8e720b>] __x64_sys_write+0x19/0x20
      [<0000000018b12cbb>] do_syscall_64+0x3f/0x90
      [<00000000986ec465>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Let's fix this calling vhost_vdpa_iotlb_unmap() on the whole range in
vhost_vdpa_remove_as(). We move that call before vhost_dev_cleanup()
since we need a valid v->vdev.mm in vhost_vdpa_pa_unmap().
vhost_iotlb_reset() call can be removed, since vhost_vdpa_iotlb_unmap()
on the whole range removes all the entries.

The kmemleak log reported was observed with a vDPA device that has `use_va`
set to true (e.g. VDUSE). This patch has been tested with both types of
devices.

## Remediation

No remediation reported in collected sources

## Affected products and versions

Not reported in collected sources.

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/4e92cb33bfb51eee5f28bb10846c46f266a4bb67 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/a2907867e2c86067accd2f011d6f23ee5533aa6c (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/c070c1912a83432530cbb4271d5b9b11fa36b67a (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

## Provenance

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-50738; retrieved 2026-11-10; source updated 2026-11-10

Revision: 774500478003aed15611112976acb1274773fc729c5e6910019c1f5707443e9f

Canonical: https://y2.dev/cve/CVE-2022-50738

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