CVE-2026-43292 (GCVE-0-2026-43292)
Vulnerability from cvelistv5 – Published: 2026-05-08 13:11 – Updated: 2026-05-09 04:10
VLAI?
Title
mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node
When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during
vmalloc cleanup triggers expensive stack unwinding that acquires RCU read
locks. Processing a large purge_list without rescheduling can cause the
task to hold CPU for extended periods (10+ seconds), leading to RCU stalls
and potential OOM conditions.
The issue manifests in purge_vmap_node() -> kasan_release_vmalloc_node()
where iterating through hundreds or thousands of vmap_area entries and
freeing their associated shadow pages causes:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l
...
task:kworker/0:17 state:R running task stack:28840 pid:6229
...
kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299
purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299
Each call to kasan_release_vmalloc() can free many pages, and with
page_owner tracking, each free triggers save_stack() which performs stack
unwinding under RCU read lock. Without yielding, this creates an
unbounded RCU critical section.
Add periodic cond_resched() calls within the loop to allow:
- RCU grace periods to complete
- Other tasks to run
- Scheduler to preempt when needed
The fix uses need_resched() for immediate response under load, with a
batch count of 32 as a guaranteed upper bound to prevent worst-case stalls
even under light load.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
282631cb2447318e2a55b41a665dbe8571c46d70 , < 2efa9c02c9b4c0d6866aa445f11056809b25ca28
(git)
Affected: 282631cb2447318e2a55b41a665dbe8571c46d70 , < 1afe45f89d54b7183768ebbbbf14238ec187ab5c (git) Affected: 282631cb2447318e2a55b41a665dbe8571c46d70 , < b351fbe71091f7c8676c8ba597653d08b6719447 (git) Affected: 282631cb2447318e2a55b41a665dbe8571c46d70 , < 5747435e0fd474c24530ef1a6822f47e7d264b27 (git) |
||
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"versions": [
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"version": "6.12.75",
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{
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"version": "6.18.16",
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node\n\nWhen CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during\nvmalloc cleanup triggers expensive stack unwinding that acquires RCU read\nlocks. Processing a large purge_list without rescheduling can cause the\ntask to hold CPU for extended periods (10+ seconds), leading to RCU stalls\nand potential OOM conditions.\n\nThe issue manifests in purge_vmap_node() -\u003e kasan_release_vmalloc_node()\nwhere iterating through hundreds or thousands of vmap_area entries and\nfreeing their associated shadow pages causes:\n\n rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:\n rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l\n ...\n task:kworker/0:17 state:R running task stack:28840 pid:6229\n ...\n kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299\n purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299\n\nEach call to kasan_release_vmalloc() can free many pages, and with\npage_owner tracking, each free triggers save_stack() which performs stack\nunwinding under RCU read lock. Without yielding, this creates an\nunbounded RCU critical section.\n\nAdd periodic cond_resched() calls within the loop to allow:\n- RCU grace periods to complete\n- Other tasks to run\n- Scheduler to preempt when needed\n\nThe fix uses need_resched() for immediate response under load, with a\nbatch count of 32 as a guaranteed upper bound to prevent worst-case stalls\neven under light load."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-09T04:10:04.732Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
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"url": "https://git.kernel.org/stable/c/2efa9c02c9b4c0d6866aa445f11056809b25ca28"
},
{
"url": "https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5c"
},
{
"url": "https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447"
},
{
"url": "https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27"
}
],
"title": "mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node",
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"assignerShortName": "Linux",
"cveId": "CVE-2026-43292",
"datePublished": "2026-05-08T13:11:16.017Z",
"dateReserved": "2026-05-01T14:12:55.999Z",
"dateUpdated": "2026-05-09T04:10:04.732Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
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"nvd": "{\"cve\":{\"id\":\"CVE-2026-43292\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-08T14:16:36.250\",\"lastModified\":\"2026-05-08T14:16:36.250\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node\\n\\nWhen CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during\\nvmalloc cleanup triggers expensive stack unwinding that acquires RCU read\\nlocks. Processing a large purge_list without rescheduling can cause the\\ntask to hold CPU for extended periods (10+ seconds), leading to RCU stalls\\nand potential OOM conditions.\\n\\nThe issue manifests in purge_vmap_node() -\u003e kasan_release_vmalloc_node()\\nwhere iterating through hundreds or thousands of vmap_area entries and\\nfreeing their associated shadow pages causes:\\n\\n rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:\\n rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l\\n ...\\n task:kworker/0:17 state:R running task stack:28840 pid:6229\\n ...\\n kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299\\n purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299\\n\\nEach call to kasan_release_vmalloc() can free many pages, and with\\npage_owner tracking, each free triggers save_stack() which performs stack\\nunwinding under RCU read lock. Without yielding, this creates an\\nunbounded RCU critical section.\\n\\nAdd periodic cond_resched() calls within the loop to allow:\\n- RCU grace periods to complete\\n- Other tasks to run\\n- Scheduler to preempt when needed\\n\\nThe fix uses need_resched() for immediate response under load, with a\\nbatch count of 32 as a guaranteed upper bound to prevent worst-case stalls\\neven under light load.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2efa9c02c9b4c0d6866aa445f11056809b25ca28\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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