FKIE_CVE-2026-43292

Vulnerability from fkie_nvd - Published: 2026-05-08 14:16 - Updated: 2026-05-14 21:04
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2efa9c02c9b4c0d6866aa445f11056809b25ca28Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

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  "descriptions": [
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      "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."
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  "id": "CVE-2026-43292",
  "lastModified": "2026-05-14T21:04:41.027",
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
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  "published": "2026-05-08T14:16:36.250",
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