---
id: CVE-2022-49810
title: 'netfs: Fix missing xas_retry() calls in xarray iteration'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfs: Fix missing xas_retry() calls in xarray iteration

  netfslib has a number of places in which it performs iteration of an xarray
  whilst being under the RCU read lo…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd <
    b2cc07a76f1eb12de3b22caf5fdbf856a7bef16d
  - >-
    Linux >= 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd <
    7e043a80b5dae5c2d2cf84031501de7827fd6c00
  - Linux 5.13
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T19:49:08.202965Z'
published: '2025-05-01'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T19:49:50.528Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2022-49810'
references:
  - url: 'https://git.kernel.org/stable/c/b2cc07a76f1eb12de3b22caf5fdbf856a7bef16d'
  - url: 'https://git.kernel.org/stable/c/7e043a80b5dae5c2d2cf84031501de7827fd6c00'
tags:
  - cve.org
epss: 0.0017
epssPercentile: 0.06464
ingestedAt: '2026-11-05T22:38:31.602Z'
---

## Overview

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

netfs: Fix missing xas_retry() calls in xarray iteration

netfslib has a number of places in which it performs iteration of an xarray
whilst being under the RCU read lock.  It *should* call xas_retry() as the
first thing inside of the loop and do "continue" if it returns true in case
the xarray walker passed out a special value indicating that the walk needs
to be redone from the root[*].

Fix this by adding the missing retry checks.

[*] I wonder if this should be done inside xas_find(), xas_next_node() and
    suchlike, but I'm told that's not an simple change to effect.

This can cause an oops like that below.  Note the faulting address - this
is an internal value (|0x2) returned from xarray.

BUG: kernel NULL pointer dereference, address: 0000000000000402
...
RIP: 0010:netfs_rreq_unlock+0xef/0x380 [netfs]
...
Call Trace:
 netfs_rreq_assess+0xa6/0x240 [netfs]
 netfs_readpage+0x173/0x3b0 [netfs]
 ? init_wait_var_entry+0x50/0x50
 filemap_read_page+0x33/0xf0
 filemap_get_pages+0x2f2/0x3f0
 filemap_read+0xaa/0x320
 ? do_filp_open+0xb2/0x150
 ? rmqueue+0x3be/0xe10
 ceph_read_iter+0x1fe/0x680 [ceph]
 ? new_sync_read+0x115/0x1a0
 new_sync_read+0x115/0x1a0
 vfs_read+0xf3/0x180
 ksys_read+0x5f/0xe0
 do_syscall_64+0x38/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Changes:
========
ver #2)
 - Changed an unsigned int to a size_t to reduce the likelihood of an
   overflow as per Willy's suggestion.
 - Added an additional patch to fix the maths.

## Affected

- `Linux >= 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd < b2cc07a76f1eb12de3b22caf5fdbf856a7bef16d`
- `Linux >= 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd < 7e043a80b5dae5c2d2cf84031501de7827fd6c00`
- `Linux 5.13`

## Remediation

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