CVE-2023-53178
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2023-53178
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53178.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2023-53178
- Downstream
- Related
- Published
- 2025-09-15T14:04:23Z
- Modified
- 2025-10-15T06:26:32.958205Z
- Summary
- mm: fix zswap writeback race condition
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
mm: fix zswap writeback race condition
The zswap writeback mechanism can cause a race condition resulting in memory corruption, where a swapped out page gets swapped in with data that was written to a different page.
The race unfolds like this: 1. a page with data A and swap offset X is stored in zswap 2. page A is removed off the LRU by zpool driver for writeback in zswap-shrink work, data for A is mapped by zpool driver 3. user space program faults and invalidates page entry A, offset X is considered free 4. kswapd stores page B at offset X in zswap (zswap could also be full, if so, page B would then be IOed to X, then skip step 5.) 5. entry A is replaced by B in tree->rbroot, this doesn't affect the local reference held by zswap-shrink work 6. zswap-shrink work writes back A at X, and frees zswap entry A 7. swapin of slot X brings A in memory instead of B
The fix: Once the swap page cache has been allocated (case ZSWAPSWAPCACHENEW), zswap-shrink work just checks that the local zswap_entry reference is still the same as the one in the tree. If it's not the same it means that it's either been invalidated or replaced, in both cases the writeback is aborted because the local entry contains stale data.
Reproducer: I originally found this by running
stressovernight to validate my work on the zswap writeback mechanism, it manifested after hours on my test machine. The key to make it happen is having zswap writebacks, so whatever setup pumps /sys/kernel/debug/zswap/writtenbackpages should do the trick.In order to reproduce this faster on a vm, I setup a system with ~100M of available memory and a 500M swap file, then running
stress --vm 1 --vm-bytes 300000000 --vm-stride 4000makes it happen in matter of tens of minutes. One can speed things up even more by swinging /sys/module/zswap/parameters/maxpoolpercent up and down between, say, 20 and 1; this makes it reproduce in tens of seconds. It's crucial to set--vm-strideto something other than 4096 otherwisestresswon't realize that memory has been corrupted because all pages would have the same data. - References
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2b2811178e85553405b86e3fe78357b9b95889ceFixed2cab13f500a6333bd2b853783ac76be9e4956f8a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2b2811178e85553405b86e3fe78357b9b95889ceFixedba700ea13bf0105a4773c654f7d3bef8adb64ab2
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2b2811178e85553405b86e3fe78357b9b95889ceFixed04fc7816089c5a32c29a04ec94b998e219dfb946
Affected versions
v3.*
v4.*
v5.*
v6.*
Database specific
{
"vanir_signatures": [
{
"signature_version": "v1",
"target": {
"function": "zswap_writeback_entry",
"file": "mm/zswap.c"
},
"signature_type": "Function",
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@ba700ea13bf0105a4773c654f7d3bef8adb64ab2",
"deprecated": false,
"digest": {
"length": 2117.0,
"function_hash": "276492150022357947427222559594200768854"
},
"id": "CVE-2023-53178-09049385"
},
{
"signature_version": "v1",
"target": {
"function": "zswap_writeback_entry",
"file": "mm/zswap.c"
},
"signature_type": "Function",
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@2cab13f500a6333bd2b853783ac76be9e4956f8a",
"deprecated": false,
"digest": {
"length": 2023.0,
"function_hash": "332166313800090419201489960471523521593"
},
"id": "CVE-2023-53178-2b292b65"
},
{
"signature_version": "v1",
"target": {
"file": "mm/zswap.c"
},
"signature_type": "Line",
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@04fc7816089c5a32c29a04ec94b998e219dfb946",
"deprecated": false,
"digest": {
"line_hashes": [
"270897931510983390821172508143958633508",
"158700890838025227639261642285697390123",
"287631605221437223990527199055239157552",
"12215852667165856966825036701112394056"
],
"threshold": 0.9
},
"id": "CVE-2023-53178-40415bd4"
},
{
"signature_version": "v1",
"target": {
"file": "mm/zswap.c"
},
"signature_type": "Line",
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@2cab13f500a6333bd2b853783ac76be9e4956f8a",
"deprecated": false,
"digest": {
"line_hashes": [
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"287631605221437223990527199055239157552",
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],
"threshold": 0.9
},
"id": "CVE-2023-53178-5d606fd7"
},
{
"signature_version": "v1",
"target": {
"function": "zswap_writeback_entry",
"file": "mm/zswap.c"
},
"signature_type": "Function",
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@04fc7816089c5a32c29a04ec94b998e219dfb946",
"deprecated": false,
"digest": {
"length": 2117.0,
"function_hash": "276492150022357947427222559594200768854"
},
"id": "CVE-2023-53178-dec10a16"
},
{
"signature_version": "v1",
"target": {
"file": "mm/zswap.c"
},
"signature_type": "Line",
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@ba700ea13bf0105a4773c654f7d3bef8adb64ab2",
"deprecated": false,
"digest": {
"line_hashes": [
"270897931510983390821172508143958633508",
"158700890838025227639261642285697390123",
"287631605221437223990527199055239157552",
"12215852667165856966825036701112394056"
],
"threshold": 0.9
},
"id": "CVE-2023-53178-e1f1b67a"
}
]
}