fkie_cve-2023-53419
Vulnerability from fkie_nvd
Published
2025-09-18 16:15
Modified
2025-09-19 16:00
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can result in a NULL-pointer dereference: CPU1 CPU2 rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL raw_spin_lock_rcu_node np = rcu_next_node_entry(t, rnp) if (&t->rcu_node_entry == rnp->exp_tasks) WRITE_ONCE(rnp->exp_tasks, np) .... raw_spin_unlock_irqrestore_rcu_node raw_spin_lock_irqsave_rcu_node t = list_entry(rnp->exp_tasks->prev, struct task_struct, rcu_node_entry) (if rnp->exp_tasks is NULL, this will dereference a NULL pointer) The problem is that CPU2 accesses the rcu_node structure's->exp_tasks field without holding the rcu_node structure's ->lock and CPU2 did not observe CPU1's change to rcu_node structure's ->exp_tasks in time. Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL, then CPU2 might dereference that NULL pointer. This commit therefore holds the rcu_node structure's ->lock while accessing that structure's->exp_tasks field. [ paulmck: Apply Frederic Weisbecker feedback. ]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2bc0ae94ef1f9ed322d8ee439de3239ea3632ab2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3c1566bca3f8349f12b75d0a2d5e4a20ad6262ec
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a7d21b8585894e6fff973f6ddae42f02b13f600f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d0a8c0e31a09ec1efd53079083e2a677956b4d91
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e30a55e98ae6c44253d8b129efefd5da5bc6e3bc
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrcu: Protect rcu_print_task_exp_stall() -\u003eexp_tasks access\n\nFor kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can\nresult in a NULL-pointer dereference:\n\n           CPU1                                           CPU2\nrcu_preempt_deferred_qs_irqrestore                rcu_print_task_exp_stall\n  if (special.b.blocked)                            READ_ONCE(rnp-\u003eexp_tasks) != NULL\n    raw_spin_lock_rcu_node\n    np = rcu_next_node_entry(t, rnp)\n    if (\u0026t-\u003ercu_node_entry == rnp-\u003eexp_tasks)\n      WRITE_ONCE(rnp-\u003eexp_tasks, np)\n      ....\n      raw_spin_unlock_irqrestore_rcu_node\n                                                    raw_spin_lock_irqsave_rcu_node\n                                                    t = list_entry(rnp-\u003eexp_tasks-\u003eprev,\n                                                        struct task_struct, rcu_node_entry)\n                                                    (if rnp-\u003eexp_tasks is NULL, this\n                                                       will dereference a NULL pointer)\n\nThe problem is that CPU2 accesses the rcu_node structure\u0027s-\u003eexp_tasks\nfield without holding the rcu_node structure\u0027s -\u003elock and CPU2 did\nnot observe CPU1\u0027s change to rcu_node structure\u0027s -\u003eexp_tasks in time.\nTherefore, if CPU1 sets rcu_node structure\u0027s-\u003eexp_tasks pointer to NULL,\nthen CPU2 might dereference that NULL pointer.\n\nThis commit therefore holds the rcu_node structure\u0027s -\u003elock while\naccessing that structure\u0027s-\u003eexp_tasks field.\n\n[ paulmck: Apply Frederic Weisbecker feedback. ]"
    }
  ],
  "id": "CVE-2023-53419",
  "lastModified": "2025-09-19T16:00:27.847",
  "metrics": {},
  "published": "2025-09-18T16:15:45.650",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2bc0ae94ef1f9ed322d8ee439de3239ea3632ab2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3c1566bca3f8349f12b75d0a2d5e4a20ad6262ec"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a7d21b8585894e6fff973f6ddae42f02b13f600f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d0a8c0e31a09ec1efd53079083e2a677956b4d91"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e30a55e98ae6c44253d8b129efefd5da5bc6e3bc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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