ghsa-pgjm-rqqp-m93m
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
tty: xilinx_uartps: split sysrq handling
lockdep detects the following circular locking dependency:
CPU 0 CPU 1 ========================== ============================ cdns_uart_isr() printk() uart_port_lock(port) console_lock() cdns_uart_console_write() if (!port->sysrq) uart_port_lock(port) uart_handle_break() port->sysrq = ... uart_handle_sysrq_char() printk() console_lock()
The fixed commit attempts to avoid this situation by only taking the port lock in cdns_uart_console_write if port->sysrq unset. However, if (as shown above) cdns_uart_console_write runs before port->sysrq is set, then it will try to take the port lock anyway. This may result in a deadlock.
Fix this by splitting sysrq handling into two parts. We use the prepare helper under the port lock and defer handling until we release the lock.
{
"affected": [],
"aliases": [
"CVE-2025-21820"
],
"database_specific": {
"cwe_ids": [
"CWE-667"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-27T20:16:04Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: xilinx_uartps: split sysrq handling\n\nlockdep detects the following circular locking dependency:\n\nCPU 0 CPU 1\n========================== ============================\ncdns_uart_isr() printk()\n uart_port_lock(port) console_lock()\n\t\t\t cdns_uart_console_write()\n if (!port-\u003esysrq)\n uart_port_lock(port)\n uart_handle_break()\n port-\u003esysrq = ...\n uart_handle_sysrq_char()\n printk()\n console_lock()\n\nThe fixed commit attempts to avoid this situation by only taking the\nport lock in cdns_uart_console_write if port-\u003esysrq unset. However, if\n(as shown above) cdns_uart_console_write runs before port-\u003esysrq is set,\nthen it will try to take the port lock anyway. This may result in a\ndeadlock.\n\nFix this by splitting sysrq handling into two parts. We use the prepare\nhelper under the port lock and defer handling until we release the lock.",
"id": "GHSA-pgjm-rqqp-m93m",
"modified": "2025-03-13T15:32:53Z",
"published": "2025-02-27T21:32:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21820"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4410dba9807a17a93f649a9f5870ceaf30a675a3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8ea0e7b3d7b8f2f0fc9db491ff22a0abe120801c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9b88a7c4584ba67267a051069b8abe44fc9595b2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b06f388994500297bb91be60ffaf6825ecfd2afe"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/de5bd24197bd9ee37ec1e379a3d882bbd15c5065"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e22a97700901ba5e8bf8db68056a0d50f9440cae"
}
],
"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"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
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