{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-35929",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2024-35929"
  ],
  "published": "2024-05-19T10:11:49Z",
  "summary": "rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock()\n\nFor the kernels built with CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y and\nCONFIG_RCU_LAZY=y, the following scenarios will trigger WARN_ON_ONCE()\nin the rcu_nocb_bypass_lock() and rcu_nocb_wait_contended() functions:\n\n        CPU2                                               CPU11\nkthread\nrcu_nocb_cb_kthread                                       ksys_write\nrcu_do_batch                                              vfs_write\nrcu_torture_timer_cb                                      proc_sys_write\n__kmem_cache_free                                         proc_sys_call_handler\nkmemleak_free                                             drop_caches_sysctl_handler\ndelete_object_full                                        drop_slab\n__delete_object                                           shrink_slab\nput_object                                                lazy_rcu_shrink_scan\ncall_rcu                                                  rcu_nocb_flush_bypass\n__call_rcu_commn                                            rcu_nocb_bypass_lock\n                                                            raw_spin_trylock(&rdp->nocb_bypass_lock) fail\n                                                            atomic_inc(&rdp->nocb_lock_contended);\nrcu_nocb_wait_contended                                     WARN_ON_ONCE(smp_processor_id() != rdp->cpu);\n WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended))                                          |\n                            |_ _ _ _ _ _ _ _ _ _same rdp and rdp->cpu != 11_ _ _ _ _ _ _ _ _ __|\n\nReproduce this bug with \"echo 3 > /proc/sys/vm/drop_caches\".\n\nThis commit therefore uses rcu_nocb_try_flush_bypass() instead of\nrcu_nocb_flush_bypass() in lazy_rcu_shrink_scan().  If the nocb_bypass\nqueue is being flushed, then rcu_nocb_try_flush_bypass will return\ndirectly.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.6.20-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-2712",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v7",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v7l",
            "binary_version": "1:6.6.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.6.20+rpt-rpi-v8",
            "binary_version": "1:6.6.20-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.6.20-1+rpt1": {
            "linux_commit": "6f16847710cc0502450788b9f12f0a14d3429668",
            "upstream_version": "6.6.20",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.27"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-35929"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4d58c9fb45c70e62c19e8be3f3605889c47601bc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/927d1f4f77e4784ab3944a9df86ab14d1cd3185a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/dda98810b552fc6bf650f4270edeebdc2f28bd3f"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}