CVE-2026-89880 — media: rtl2832_sdr: release URBs and stream buffers on start_streaming() failure

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

media: rtl2832_sdr: release URBs and stream buffers on start_streaming() failure

rtl2832_sdr_start_streaming() calls rtl2832_sdr_alloc_stream_bufs(), rtl2832_sdr_alloc_urbs() and rtl2832_sdr_submit_urbs() in sequence and shares a single err: label that only unlocks the mutex and returns. When alloc_urbs() succeeds but submit_urbs() fails, or when alloc_urbs() itself returns -ENOMEM after alloc_stream_bufs() has already succeeded, the URBs and/or the coherent DMA stream buffers stay allocated while streaming reports failure to vb2. Two latent defects follow on the next VIDIOC_STREAMON:

1) rtl2832_sdr_alloc_stream_bufs() unconditionally resets dev->buf_num to 0 and overwrites dev->buf_list[]/dev->dma_addr[], permanently leaking the coherent DMA memory allocated by the previous attempt.

2) rtl2832_sdr_alloc_urbs() never resets dev->urbs_initialized and only increments it. After a second successful pass urbs_initialized can exceed MAX_BULK_BUFS, so the subsequent rtl2832_sdr_free_urbs() walks from urbs_initialized - 1 down to 0 and reads past the end of dev->urb_list[], passing garbage pointers to usb_free_urb().

Mirror the teardown that stop_streaming() already performs: on the error path call rtl2832_sdr_free_urbs() and rtl2832_sdr_free_stream_bufs() before unlocking. Both helpers are idempotent (free_urbs kills and zeros urbs_initialized; free_stream_bufs is gated on URB_BUF and clears…

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CVE-2026-89880 — media: rtl2832_sdr: release URBs and stream buffers on start_streaming() failure