{"id":69583,"date":"2025-09-05T23:32:10","date_gmt":"2025-09-05T20:02:10","guid":{"rendered":"https:\/\/afaghhosting.net\/blog\/cve-2025-39724-serial-8250-fix-panic-due-to-pslverr\/"},"modified":"2025-09-05T23:32:10","modified_gmt":"2025-09-05T20:02:10","slug":"cve-2025-39724-serial-8250-fix-panic-due-to-pslverr","status":"publish","type":"post","link":"https:\/\/afaghhosting.net\/blog\/cve-2025-39724-serial-8250-fix-panic-due-to-pslverr\/","title":{"rendered":"CVE-2025-39724 &#8211; serial: 8250: fix panic due to PSLVERR"},"content":{"rendered":"<p><strong>CVE ID : <\/strong>CVE-2025-39724<br \/>\n<br \/>\n<strong>Published : <\/strong> Sept. 5, 2025, 6:15 p.m. | 1\u00a0hour ago<br \/>\n<br \/>\n<strong>Description : <\/strong>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>serial: 8250: fix panic due to PSLVERR<\/p>\n<p>When the PSLVERR_RESP_EN parameter is set to 1, the device generates<br \/>\nan error response if an attempt is made to read an empty RBR (Receive<br \/>\nBuffer Register) while the FIFO is enabled.<\/p>\n<p>In serial8250_do_startup(), calling serial_port_out(port, UART_LCR,<br \/>\nUART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes<br \/>\ndw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter<br \/>\nfunction enables the FIFO via serial_out(p, UART_FCR, p-&gt;fcr).<br \/>\nExecution proceeds to the serial_port_in(port, UART_RX).<br \/>\nThis satisfies the PSLVERR trigger condition.<\/p>\n<p>When another CPU (e.g., using printk()) is accessing the UART (UART<br \/>\nis busy), the current CPU fails the check (value &amp; ~UART_LCR_SPAR) ==<br \/>\n(lcr &amp; ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter<br \/>\ndw8250_force_idle().<\/p>\n<p>Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port-&gt;lock<br \/>\nto fix this issue.<\/p>\n<p>Panic backtrace:<br \/>\n[    0.442336] Oops &#8211; unknown exception [#1]\n[    0.442343] epc : dw8250_serial_in32+0x1e\/0x4a<br \/>\n[    0.442351]  ra : serial8250_do_startup+0x2c8\/0x88e<br \/>\n&#8230;<br \/>\n[    0.442416] console_on_rootfs+0x26\/0x70<br \/>\n<br \/>\n<strong>Severity:<\/strong> 0.0 | NA<br \/>\n<br \/>\nVisit the link for more details, such as CVSS details, affected products, timeline, and more&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>CVE ID : CVE-2025-39724 Published : Sept. 5, 2025, 6:15 p.m. | 1\u00a0hour ago Description : 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 &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-69583","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/69583","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=69583"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/69583\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=69583"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=69583"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=69583"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}