Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  media: dvb-core: fix wrong reinitialization of ringbuffer on reopen  dvb_dvr_open() calls dvb_ringbuffer_init() when a new reader opens the DVR device.  dvb_ringbuffer_init() calls init_waitqueue_head(), which reinitializes the waitqueue list head to empty.  Since dmxdev->dvr_buffer.queue is a shared waitqueue (all opens of the same DVR device share it), this orphans any existing waitqueue entries from io_uring poll or epoll, leaving them with stale prev/next pointers while the list head is reset to {self, self}.  The waitqueue and spinlock in dvr_buffer are already properly initialized once in dvb_dmxdev_init().  The open path only needs to reset the buffer data pointer, size, and read/write positions.  Replace the dvb_ringbuffer_init() call in dvb_dvr_open() with direct assignment of data/size and a call to dvb_ringbuffer_reset(), which properly resets pread, pwrite, and error with correct memory ordering without touching the waitqueue or spinlock.