CVE-2022-49810

netfs: Fix missing xas_retry() calls in xarray iteration

Published May 1, 2025 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
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 solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-12962 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.
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-476
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.1:rc5:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description 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.
Title netfs: Fix missing xas_retry() calls in xarray iteration
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Nov 5, 2026, 7:49 PM
Reserved
May 1, 2025, 2:05 PM
Status
Analyzed
Published
May 1, 2025, 3:16 PM
Modified
Nov 5, 2026, 8:17 PM
Severity
Moderate
Public date
May 1, 2025, 12:00 AM