CVE-2026-43292
Full vulnerability record from the local CVENow database.
Description
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.
View original CVE JSON
{
"id": "CVE-2026-43292",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-05-08T14:16:36.250",
"lastModified": "2026-11-06T16:18:32.927",
"vulnStatus": "Analyzed",
"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() -> 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."
}
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"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
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"id": "CVE-2026-43292",
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