# CVE-2022-49810: netfs: Fix missing xas_retry() calls in xarray iteration

Status: published. Published: 2025-05-01. Updated: 2026-11-05.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd; < b2cc07a76f1eb12de3b22caf5fdbf856a7bef16d (affected, git); ≥ 3d3c95046742e4eebaa4b891b0b01cbbed94ebbd; < 7e043a80b5dae5c2d2cf84031501de7827fd6c00 (affected, git). Source: CNA: Linux
- Linux / Linux: 5.13 (affected); ≥ 0; < 5.13 (unaffected, semver); ≥ 6.0.10; ≤ 6.0.* (unaffected, semver); ≥ 6.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.17% as of 2026-11-05; percentile 6.47%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- 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/b2cc07a76f1eb12de3b22caf5fdbf856a7bef16d (CNA: Linux)

- https://git.kernel.org/stable/c/7e043a80b5dae5c2d2cf84031501de7827fd6c00 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2022-49810; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2022-49810; retrieved 2026-11-05; source updated Not reported

Revision: 055e9e0d8d8d4131224d5eb7ee4f08ce861f21324d96cf64af533bdf9dfa6ca8

Canonical: https://y2.dev/cve/CVE-2022-49810

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