In the Linux kernel, the following vulnerability has been resolved: nfc: pn533: Fix use-after-free bugs caused by pn532_cmd_timeout When the pn532 uart device is detaching, the pn532_uart_remove() is called. But there are no functions in pn532_uart_remove() that could delete the cmd_timeout timer, which will cause use-after-free bugs. The process is shown below: (thread 1) | (thread 2) | pn532_uart_send_frame pn532_uart_remove | mod_timer(&pn532->cmd_timeout,...) ... | (wait a time) kfree(pn532) //FREE | pn532_cmd_timeout | pn532_uart_send_frame | pn532->... //USE This patch adds del_timer