fkie_cve-2025-39724
Vulnerability from fkie_nvd
Published
2025-09-05 18:15
Modified
2025-09-08 16:25
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: serial: 8250: fix panic due to PSLVERR When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled. In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition. When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle(). Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue. Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0b882f00655afefbc7729c6b5aec86f7a5473a3d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/38c0ea484dedb58cb3a4391229933e16be0d1031
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/68c4613e89f000e8198f9ace643082c697921c9f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7f8fdd4dbffc05982b96caf586f77a014b2a9353
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8e2739478c164147d0774802008528d9e03fb802
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b8ca8e3f75ede308b4d49a6ca5081460be01bdb5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c826943abf473a3f7260fbadfad65e44db475460
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cb7b3633ed749db8e56f475f43c960652cbd6882
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nserial: 8250: fix panic due to PSLVERR\n\nWhen the PSLVERR_RESP_EN parameter is set to 1, the device generates\nan error response if an attempt is made to read an empty RBR (Receive\nBuffer Register) while the FIFO is enabled.\n\nIn serial8250_do_startup(), calling serial_port_out(port, UART_LCR,\nUART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes\ndw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter\nfunction enables the FIFO via serial_out(p, UART_FCR, p-\u003efcr).\nExecution proceeds to the serial_port_in(port, UART_RX).\nThis satisfies the PSLVERR trigger condition.\n\nWhen another CPU (e.g., using printk()) is accessing the UART (UART\nis busy), the current CPU fails the check (value \u0026 ~UART_LCR_SPAR) ==\n(lcr \u0026 ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter\ndw8250_force_idle().\n\nPut serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port-\u003elock\nto fix this issue.\n\nPanic backtrace:\n[    0.442336] Oops - unknown exception [#1]\n[    0.442343] epc : dw8250_serial_in32+0x1e/0x4a\n[    0.442351]  ra : serial8250_do_startup+0x2c8/0x88e\n...\n[    0.442416] console_on_rootfs+0x26/0x70"
    }
  ],
  "id": "CVE-2025-39724",
  "lastModified": "2025-09-08T16:25:38.810",
  "metrics": {},
  "published": "2025-09-05T18:15:50.177",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0b882f00655afefbc7729c6b5aec86f7a5473a3d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/38c0ea484dedb58cb3a4391229933e16be0d1031"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/68c4613e89f000e8198f9ace643082c697921c9f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7f8fdd4dbffc05982b96caf586f77a014b2a9353"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8e2739478c164147d0774802008528d9e03fb802"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b8ca8e3f75ede308b4d49a6ca5081460be01bdb5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c826943abf473a3f7260fbadfad65e44db475460"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cb7b3633ed749db8e56f475f43c960652cbd6882"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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