GHSA-XW48-XGG9-9H3G

Vulnerability from github – Published: 2026-05-08 15:31 – Updated: 2026-05-26 15:32
VLAI
Details

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

powerpc, perf: Check that current->mm is alive before getting user callchain

It may happen that mm is already released, which leads to kernel panic. This adds the NULL check for current->mm, similarly to commit 20afc60f892d ("x86, perf: Check that current->mm is alive before getting user callchain").

I was getting this panic when running a profiling BPF program (profile.py from bcc-tools):

[26215.051935] Kernel attempted to read user page (588) - exploit attempt? (uid: 0)
[26215.051950] BUG: Kernel NULL pointer dereference on read at 0x00000588
[26215.051952] Faulting instruction address: 0xc00000000020fac0
[26215.051957] Oops: Kernel access of bad area, sig: 11 [#1]
[...]
[26215.052049] Call Trace:
[26215.052050] [c000000061da6d30] [c00000000020fc10] perf_callchain_user_64+0x2d0/0x490 (unreliable)
[26215.052054] [c000000061da6dc0] [c00000000020f92c] perf_callchain_user+0x1c/0x30
[26215.052057] [c000000061da6de0] [c0000000005ab2a0] get_perf_callchain+0x100/0x360
[26215.052063] [c000000061da6e70] [c000000000573bc8] bpf_get_stackid+0x88/0xf0
[26215.052067] [c000000061da6ea0] [c008000000042258] bpf_prog_16d4ab9ab662f669_do_perf_event+0xf8/0x274
[...]

In addition, move storing the top-level stack entry to generic perf_callchain_user to make sure the top-evel entry is always captured, even if current->mm is NULL.

[Maddy: fixed message to avoid checkpatch format style error]

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-43416"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-08T15:16:53Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc, perf: Check that current-\u003emm is alive before getting user callchain\n\nIt may happen that mm is already released, which leads to kernel panic.\nThis adds the NULL check for current-\u003emm, similarly to\ncommit 20afc60f892d (\"x86, perf: Check that current-\u003emm is alive before getting user callchain\").\n\nI was getting this panic when running a profiling BPF program\n(profile.py from bcc-tools):\n\n    [26215.051935] Kernel attempted to read user page (588) - exploit attempt? (uid: 0)\n    [26215.051950] BUG: Kernel NULL pointer dereference on read at 0x00000588\n    [26215.051952] Faulting instruction address: 0xc00000000020fac0\n    [26215.051957] Oops: Kernel access of bad area, sig: 11 [#1]\n    [...]\n    [26215.052049] Call Trace:\n    [26215.052050] [c000000061da6d30] [c00000000020fc10] perf_callchain_user_64+0x2d0/0x490 (unreliable)\n    [26215.052054] [c000000061da6dc0] [c00000000020f92c] perf_callchain_user+0x1c/0x30\n    [26215.052057] [c000000061da6de0] [c0000000005ab2a0] get_perf_callchain+0x100/0x360\n    [26215.052063] [c000000061da6e70] [c000000000573bc8] bpf_get_stackid+0x88/0xf0\n    [26215.052067] [c000000061da6ea0] [c008000000042258] bpf_prog_16d4ab9ab662f669_do_perf_event+0xf8/0x274\n    [...]\n\nIn addition, move storing the top-level stack entry to generic\nperf_callchain_user to make sure the top-evel entry is always captured,\neven if current-\u003emm is NULL.\n\n[Maddy: fixed message to avoid checkpatch format style error]",
  "id": "GHSA-xw48-xgg9-9h3g",
  "modified": "2026-05-26T15:32:08Z",
  "published": "2026-05-08T15:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43416"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e5f60b8cfc02a2b23a40a5f5fd2fa81d010e737"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/98074e16742ae87fb82e234b419783c5ffc9baea"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e9bbfb4bfa86c6b5515b868d6982ac60505d7e39"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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