serial: amba-pl011: keep console clock enabled for atomic writes

{
  "id": "5998c9e0b4d3bb318ecaea68d2d7d478c02135828199cd15bc41e9b2da1556f2",
  "url": "https://osv.dev/vulnerability/CVE-2026-90338",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "serial: amba-pl011: keep console clock enabled for atomic writes",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: serial: amba-pl011: keep console clock enabled for atomic writes pl011_console_write_atomic() runs from nbcon atomic context, where sleeping is not allowed. It calls clk_enable(), which takes the common-clk enable_lock. Under PREEMPT_RT that is a sleeping lock: clk_enable_lock() first tries spin_trylock_irqsave(), but on contention falls back to spin_lock_irqsave(). Therefore, an atomic-context printk on an RT kernel with a clk-backed pl011 can trip: BUG: sleeping function called from invalid context at spinlock_rt.c:48 __might_resched from rt_spin_lock rt_spin_lock from clk_enable_lock clk_enable_lock from clk_enable clk_enable from pl011_console_write_atomic ... from vprintk_emit This was found and reproduced on PREEMPT_RT. Arm32 and arm64 DT SoCs are affected; arm64 SBSA/ACPI has no clk, so clk_enable(NULL) short-circuits before the lock. In addition, write_atomic() may be invoked from NMI context and is documented to avoid locking. Removing clk_enable() from the callback also avoids a potentially unsafe NMI acquisition of the common-clock enable_lock. An nbcon atomic-capable console must be printable from any context, so the clock cannot be gated between writes. Enable the clock while the console is available for output: use clk_prepare_enable() in pl011_console_setup(), release it via clk_disable_unprepare() in the console .exit() callback, and drop the per-write clk_enable()/clk_disable() pairs from wri",
    "evidence": "osv:CVE-2026-90338",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90338",
      "aliases": [
        "CVE-2026-90338"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2eb2608618ce5878e11bbe68cc8d2699c8f3a81a"
                },
                {
                  "fixed": "5b77848423f4a5a362dcc3caedcdc1a75d0758c3"
                },
                {
                  "fixed": "2ad24c1d0b939d814a3020f96a667ac2d0394289"
                },
                {
                  "fixed": "c0e8cfef754645856374e82c8effd54b7d82002b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90338.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.15.0"
                },
                {
                  "fixed": "6.18.52"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90338.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.580970176Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2ad24c1d0b939d814a3020f96a667ac2d0394289",
        "https://git.kernel.org/stable/c/5b77848423f4a5a362dcc3caedcdc1a75d0758c3",
        "https://git.kernel.org/stable/c/c0e8cfef754645856374e82c8effd54b7d82002b",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90338.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90338",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90338.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90338",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 492190,
  "published_at": "2026-09-17T16:08:50.331+00:00"
}