GHSA-9GFG-CJVV-9789

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31
VLAI
Details

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

tty: serial: samsung: Remove redundant port lock acquisition in rx helpers

Sashiko identified a deadlock when the console flow is engaged [1].

When console flow control is enabled (UPF_CONS_FLOW), s3c24xx_serial_stop_tx() calls s3c24xx_serial_rx_enable() and s3c24xx_serial_start_tx() calls s3c24xx_serial_rx_disable().

The serial core framework invokes the .stop_tx() and .start_tx() callbacks with the port->lock spinlock already held. Furthermore, all internal driver paths that invoke stop_tx (such as the DMA TX completion handler s3c24xx_serial_tx_dma_complete() or the PIO TX IRQ handler s3c24xx_serial_tx_irq()) also acquire port->lock prior to calling it. (Note that s3c24xx_serial_start_tx() is only invoked by the serial core).

However, s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable() unconditionally attempt to acquire port->lock again using uart_port_lock_irqsave(). Since spinlocks are not recursive, this causes a deadlock on the same CPU when console flow control is engaged.

Remove the redundant lock acquisition from both rx helper functions.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64528"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:39Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: serial: samsung: Remove redundant port lock acquisition in rx helpers\n\nSashiko identified a deadlock when the console flow is engaged [1].\n\nWhen console flow control is enabled (UPF_CONS_FLOW),\ns3c24xx_serial_stop_tx() calls s3c24xx_serial_rx_enable() and\ns3c24xx_serial_start_tx() calls s3c24xx_serial_rx_disable().\n\nThe serial core framework invokes the .stop_tx() and .start_tx()\ncallbacks with the port-\u003elock spinlock already held. Furthermore, all\ninternal driver paths that invoke stop_tx (such as the DMA TX\ncompletion handler s3c24xx_serial_tx_dma_complete() or the PIO TX IRQ\nhandler s3c24xx_serial_tx_irq()) also acquire port-\u003elock prior to\ncalling it. (Note that s3c24xx_serial_start_tx() is only invoked by the\nserial core).\n\nHowever, s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable()\nunconditionally attempt to acquire port-\u003elock again using\nuart_port_lock_irqsave(). Since spinlocks are not recursive, this\ncauses a deadlock on the same CPU when console flow control is engaged.\n\nRemove the redundant lock acquisition from both rx helper functions.",
  "id": "GHSA-9gfg-cjvv-9789",
  "modified": "2026-07-25T12:31:39Z",
  "published": "2026-07-25T12:31:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64528"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/10014eb7eee351f7b587f8ac85830f0c9343cb9a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/14143ec10d69f42806b5d7b046f0fd1b835831ae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c92b42207978559e32903c3098aaf5c5b5788b2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9fd48937046efc9abb89379d63ee9cc5c661d711"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a3bb136bff5e6a5e48cdd813246c9c4686feaaa9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a9c22e0f93ba18322a6623ecdda2f0cd858ca350"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee9eb72be95490602c493db050c73d925c3a4d74"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f4c3e63fa8639aedf96fb200d9939945a9eed51e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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