GHSA-3J98-4VRC-2FPM

Vulnerability from github – Published: 2026-05-28 12:30 – Updated: 2026-05-28 12:30
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()

When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func() invokes the subsystem's ext->regfunc() before attempting to install the new probe via func_add(). If func_add() then fails (for example, when allocate_probes() cannot allocate a new probe array under memory pressure and returns -ENOMEM), the function returns the error without calling the matching ext->unregfunc(), leaving the side effects of regfunc() behind with no installed probe to justify them.

For syscall tracepoints this is particularly unpleasant: syscall_regfunc() bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task. After a leaked failure, the refcount is stuck at a non-zero value with no consumer, and every task continues paying the syscall trace entry/exit overhead until reboot. Other subsystems providing regfunc()/unregfunc() pairs exhibit similarly scoped persistent state.

Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the func_add() error path, gated on the same condition used there so the unwind is symmetric with the registration.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-46196"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-28T10:16:35Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()\n\nWhen a tracepoint goes through the 0 -\u003e 1 transition, tracepoint_add_func()\ninvokes the subsystem\u0027s ext-\u003eregfunc() before attempting to install the\nnew probe via func_add(). If func_add() then fails (for example, when\nallocate_probes() cannot allocate a new probe array under memory pressure\nand returns -ENOMEM), the function returns the error without calling the\nmatching ext-\u003eunregfunc(), leaving the side effects of regfunc() behind\nwith no installed probe to justify them.\n\nFor syscall tracepoints this is particularly unpleasant: syscall_regfunc()\nbumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task.\nAfter a leaked failure, the refcount is stuck at a non-zero value with no\nconsumer, and every task continues paying the syscall trace entry/exit\noverhead until reboot. Other subsystems providing regfunc()/unregfunc()\npairs exhibit similarly scoped persistent state.\n\nMirror the existing 1 -\u003e 0 cleanup and call ext-\u003eunregfunc() in the\nfunc_add() error path, gated on the same condition used there so the\nunwind is symmetric with the registration.",
  "id": "GHSA-3j98-4vrc-2fpm",
  "modified": "2026-05-28T12:30:32Z",
  "published": "2026-05-28T12:30:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46196"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/247ed8a969f981bfba3112fd4bb441eaa6cef59c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2c5b8eeea006eb694c81631cd5713d494b80be90"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/342829e042ac00f3d68d442ea92873fb6683f494"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7bcadb3c2bc1cf60690e931aadd35fb7bd646a49"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fad217e16fded7f3c09f8637b0f6a224d58b5f2e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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