---
id: CVE-2026-97952
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sunvdc: unmap LDC cookies when the descriptor send fails

  __send_request() maps the request's pages into the LDC channel's map
  table (ldc_map_sg()), fills in the descri…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sunvdc: unmap LDC cookies when the descriptor send fails

  __send_request() maps the request's pages into the LDC channel's map
  table (ldc_map_sg()), fills in the descri…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec <
    ab81a5c1014a38dab0fb402609fd866b0bcb4726
  - >-
    Linux >= a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec <
    57835952566f0be9b365a6eb3a70b397a9d5ef47
  - >-
    Linux >= a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec <
    f3322baa3a8ac87730feae952c1146269d78e098
  - >-
    Linux >= a11f6ca9aef989b56cd31ff4ee2af4fb31a172ec <
    0c6da21fa35e03fc74f09895433ccd6d4a9c3530
  - Linux 627e656239c63d8a81672d08de7885e89c12fa75
  - Linux a1ef7d5da9b2c145f811a80bb8197df6037a7572
  - Linux 7ab4b6526fdcdfa7772984bbcd2ac4fd14fa223b
  - Linux 3fbba4e55051d01a72b56ea192064175924bf56a
  - Linux 3e380fc2ae4d18210eec9c472b12e2b2544f7dc1
  - Linux >= 4.4.175 < 4.5
  - Linux >= 4.9.156 < 4.10
  - Linux >= 4.14.99 < 4.15
  - Linux >= 4.19.21 < 4.20
  - Linux >= 4.20.8 < 4.21
  - Linux 5.0
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:22.790'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97952'
references:
  - url: 'https://git.kernel.org/stable/c/0c6da21fa35e03fc74f09895433ccd6d4a9c3530'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/57835952566f0be9b365a6eb3a70b397a9d5ef47'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ab81a5c1014a38dab0fb402609fd866b0bcb4726'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f3322baa3a8ac87730feae952c1146269d78e098'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.878Z'
---

## Overview

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

sunvdc: unmap LDC cookies when the descriptor send fails

__send_request() maps the request's pages into the LDC channel's map
table (ldc_map_sg()), fills in the descriptor and marks it
VIO_DESC_READY before ringing the doorbell via __vdc_tx_trigger().
When the trigger fails, the error path only prints a message: the
descriptor stays READY and the cookies are never unmapped. The
mapping is normally released in vdc_end_one() when the peer completes
the descriptor - but a descriptor whose doorbell was never sent will
never complete, and since dr->prod is not advanced on failure, the
reset path (vdc_requeue_inflight(), which walks [cons, prod)) never
visits it either. The map table entries are leaked permanently.

Since commit a11f6ca9aef9 ("sunvdc: Do not spin in an infinite loop
when vio_ldc_send() returns EAGAIN") trigger failures occur in
practice under load, so every resulting I/O error also leaks one
request's worth of entries from the fixed-size (8192 entries per
channel) map table. Because the allocator hands out contiguous
ranges, fragmentation makes large multi-segment requests fail first
as the table drains, until ldc_map_sg() fails permanently and the
disk is dead until reboot.

It also makes any retry-based recovery unusable: requeuing the
request on -EAGAIN remaps the pages on every attempt, overwriting
desc->cookies and orphaning the previous mapping, so the table
drains at the retry rate. This is the memory exhaustion observed
when the requeue approach was first tested in October 2025.

Roll back on failure: unmap the cookies, mark the descriptor FREE
again and clear the request entry. If the trigger failed with
-ENOTCONN, __vdc_tx_trigger() has already reset the port, which
tears down and reallocates both the dring and the LDC channel
including its map table - nothing to roll back, and the stale
descriptor must not be touched.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.