mm: cachestat: fix two shmem bugs
When cachestat on shmem races with swapping and invalidation, there
are two possible bugs:
1) A swapin error can have resulted in a poisoned swap entry in the
shmem inode's xarray. Calling get_shadow_from_swap_cache() on it
will result in an out-of-bounds access to swapper_spaces[].
Validate the entry with non_swap_entry() before going further.
2) When we find a valid swap entry in the shmem's inode, the shadow
entry in the swapcache might not exist yet: swap IO is still in
progress and we're before __remove_mapping; swapin, invalidation,
or swapoff have removed the shadow from swapcache after we saw the
shmem swap entry.
This will send a NULL to workingset_test_recent(). The latter
purely operates on pointer bits, so it won't crash - node 0, memcg
ID 0, eviction timestamp 0, etc. are all valid inputs - but it's a
bogus test. In theory that could result in a false "recently
evicted" count.
Such a false positive wouldn't be the end of the world. But for
code clarity and (future) robustness, be explicit about this case.
Bail on get_shadow_from_swap_cache() returning NULL.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Ubuntu USN |
USN-6816-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6817-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6817-2 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-6817-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6878-1 | Linux kernel (Oracle) vulnerabilities |
Fri, 19 Sep 2025 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:* |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Tue, 12 Nov 2024 17:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-787 | |
| Metrics |
cvssV3_1
|
cvssV3_1
|
Wed, 06 Nov 2024 08:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 11 Sep 2024 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat
Redhat enterprise Linux |
|
| CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
|
| Vendors & Products |
Redhat
Redhat enterprise Linux |
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T20:11:13.892Z
Reserved: 2024-05-17T12:19:12.340Z
Link: CVE-2024-35797
Updated: 2024-08-02T03:21:47.505Z
Status : Analyzed
Published: 2024-05-17T14:15:11.937
Modified: 2025-09-19T14:53:03.730
Link: CVE-2024-35797
OpenCVE Enrichment
No data.
Ubuntu USN