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CVE-2025-21889 (GCVE-0-2025-21889)

Vulnerability from cvelistv5 – Published: 2025-03-27 14:57 – Updated: 2026-08-05 11:55
VLAI
Title
perf/core: Add RCU read lock protection to perf_iterate_ctx()
Summary
In the Linux kernel, the following vulnerability has been resolved: perf/core: Add RCU read lock protection to perf_iterate_ctx() The perf_iterate_ctx() function performs RCU list traversal but currently lacks RCU read lock protection. This causes lockdep warnings when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y: WARNING: suspicious RCU usage kernel/events/core.c:8168 RCU-list traversed in non-reader section!! Call Trace: lockdep_rcu_suspicious ? perf_event_addr_filters_apply perf_iterate_ctx perf_event_exec begin_new_exec ? load_elf_phdrs load_elf_binary ? lock_acquire ? find_held_lock ? bprm_execve bprm_execve do_execveat_common.isra.0 __x64_sys_execve do_syscall_64 entry_SYSCALL_64_after_hwframe This protection was previously present but was removed in commit bd2756811766 ("perf: Rewrite core context handling"). Add back the necessary rcu_read_lock()/rcu_read_unlock() pair around perf_iterate_ctx() call in perf_event_exec(). [ mingo: Use scoped_guard() as suggested by Peter ]
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bd27568117664b8b3e259721393df420ed51f57b , < f390c2eea571945f357a2d3b9fcb1c015767132e (git)
Affected: bd27568117664b8b3e259721393df420ed51f57b , < a2475ccad6120546ea45dbcd6cd1f74dc565ef6b (git)
Affected: bd27568117664b8b3e259721393df420ed51f57b , < dd536566dda9a551fc2a2acfab5313a5bb13ed02 (git)
Affected: bd27568117664b8b3e259721393df420ed51f57b , < 0fe8813baf4b2e865d3b2c735ce1a15b86002c74 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.2
Unaffected: 0 , < 6.2 (semver)
Unaffected: 6.6.81 , ≤ 6.6.* (semver)
Unaffected: 6.12.18 , ≤ 6.12.* (semver)
Unaffected: 6.13.6 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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              "value": "AV:L - The vulnerable path is entered through local syscalls only \u2014 `execve()` reaching `perf_event_exec()` via `begin_new_exec()`, with the racing side driven by `perf_event_open()`/`close()`. No network or remote input reaches this code.\nAC:L - The attacker controls both sides of the race, looping `execve()` in one process while closing perf event fds attached to it from another, and can widen the window arbitrarily via CPU pinning and the cross-CPU IPI that `perf_event_stop()` issues inside the unprotected walk. Nothing about the trigger depends on conditions outside the attacker\u0027s influence.\nPR:L - An ordinary unprivileged user suffices: `sysctl_perf_event_paranoid` defaults to 2, which permits task-bound user-space perf events on same-uid processes, and no capability is checked anywhere on the `execve()` side of the race.\nUI:N - Both the exec\u0027ing process and the event-closing process are attacker-controlled; no victim action or cooperation is needed.\nS:U - The corruption stays within the kernel\u0027s own security authority \u2014 a standard local kernel memory-safety flaw with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The unprotected RCU walk dereferences a freed `struct perf_event`, and the reclaimed slot can be groomed with attacker-sprayed perf events, giving a use-after-free read primitive that leaks kernel memory and pointers.\nI:H - `perf_event_addr_filters_exec()` writes into the freed object \u2014 zeroing `addr_filter_ranges[count].start/.size` through a pointer read out of reclaimed memory and incrementing `addr_filters_gen` \u2014 yielding an attacker-influenced kernel write suitable for privilege escalation.\nA:H - Traversing a freed list entry corrupts the walk and readily produces list corruption, an oops, or a full kernel panic, and the race can be retriggered in a loop."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    "datePublished": "2025-03-27T14:57:15.897Z",
    "dateReserved": "2024-12-29T08:45:45.782Z",
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This causes lockdep warnings\\nwhen running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y:\\n\\n\\tWARNING: suspicious RCU usage\\n\\tkernel/events/core.c:8168 RCU-list traversed in non-reader section!!\\n\\n\\t Call Trace:\\n\\t  lockdep_rcu_suspicious\\n\\t  ? perf_event_addr_filters_apply\\n\\t  perf_iterate_ctx\\n\\t  perf_event_exec\\n\\t  begin_new_exec\\n\\t  ? load_elf_phdrs\\n\\t  load_elf_binary\\n\\t  ? lock_acquire\\n\\t  ? find_held_lock\\n\\t  ? bprm_execve\\n\\t  bprm_execve\\n\\t  do_execveat_common.isra.0\\n\\t  __x64_sys_execve\\n\\t  do_syscall_64\\n\\t  entry_SYSCALL_64_after_hwframe\\n\\nThis protection was previously present but was removed in commit\\nbd2756811766 (\\\"perf: Rewrite core context handling\\\"). Add back the\\nnecessary rcu_read_lock()/rcu_read_unlock() pair around\\nperf_iterate_ctx() call in perf_event_exec().\\n\\n[ mingo: Use scoped_guard() as suggested by Peter ]\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: perf/core: A\u00f1adir protecci\u00f3n de bloqueo de lectura de RCU a perf_iterate_ctx(). La funci\u00f3n perf_iterate_ctx() recorre la lista de RCU, pero actualmente carece de protecci\u00f3n de bloqueo de lectura de RCU. Esto genera advertencias de lockdep al ejecutar perf probe con unshare(1) en CONFIG_PROVE_RCU_LIST=y: ADVERTENCIA: uso sospechoso de RCU kernel/events/core.c:8168 \u00a1Lista de RCU recorrida en la secci\u00f3n de no lectura! Rastreo de llamadas: lockdep_rcu_suspicious ? perf_event_addr_filters_apply perf_iterate_ctx perf_event_exec begin_new_exec ? load_elf_phdrs load_elf_binary ? lock_acquire ? find_held_lock ? bprm_execve bprm_execve do_execveat_common.isra.0 __x64_sys_execve do_syscall_64 entry_SYSCALL_64_after_hwframe Esta protecci\u00f3n ya exist\u00eda, pero se elimin\u00f3 en la confirmaci\u00f3n bd2756811766 (\\\"perf: Reescribir la gesti\u00f3n del contexto principal\\\"). Se ha a\u00f1adido de nuevo el par necesario rcu_read_lock()/rcu_read_unlock() en la llamada a perf_iterate_ctx() en perf_event_exec(). 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    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-09-13T07:55:33+00:00",
      "cve": "CVE-2025-21889",
      "id": "CVE-2025-21889",
      "initial_release_date": "2025-03-27T00:00:00+00:00",
      "product_status:known_affected": "226",
      "product_status:known_not_affected": "48",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: perf/core: Add RCU read lock protection to perf_iterate_ctx()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21889.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-30T02:04:21Z",
      "cve": "CVE-2025-21889",
      "id": "CVE-2025-21889",
      "initial_release_date": "2025-03-28T03:00:40Z",
      "product_status:known_affected": "504",
      "product_status:known_not_affected": "317",
      "product_status:recommended": "384",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-21889",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-21889.json",
      "version": "50"
    }
  }
}



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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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