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CVE-2026-89881

media: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA leak

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved: media: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA leak rtl2832_sdr_remove() runs on USB disconnect and clears dev->udev to NULL before any pending streaming teardown has run. When user space later closes its file descriptor, vb2 calls rtl2832_sdr_stop_streaming() which in turn calls rtl2832_sdr_free_stream_bufs(). That helper releases each coherent buffer with: usb_free_coherent(dev->udev, dev->buf_size, dev->buf_list[dev->buf_num], dev->dma_addr[dev->buf_num]); usb_free_coherent() returns immediately when its dev argument is NULL, so every DMA stream buffer that was live at disconnect is silently leaked. The URBs allocated in rtl2832_sdr_alloc_urbs() outlive the device for the same reason. The rtl2832_sdr driver uses vb2_fop_release() in its file_operations, so replace video_unregister_device(&dev->vdev) with vb2_video_unregister_device(&dev->vdev) and move it before clearing dev->udev. vb2_video_unregister_device() releases the vb2 queue, which synchronously runs rtl2832_sdr_stop_streaming() if streaming is active, so URBs and coherent DMA stream buffers are freed while dev->udev is still valid. vb2_video_unregister_device() locks vdev->queue->lock (vb_queue_lock) internally, and stop_streaming() locks v4l2_lock, so the previous outer mutex_lock(&dev->vb_queue_lock) / mutex_lock(&dev->v4l2_lock) pair around the unregister sequence would self-deadlock and has been removed. A short v4l2_lock critical section around dev->udev = NULL remains so any ioctl path that still holds the file descriptor sees coherent state. Issue identified by automated review of the INV-003 series at https://sashiko.dev/

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in 234c46b95a032232e31fa5987b84fb8f87a9693b; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in 034b6a4f9589c04bc3f2bd5125658cd72d3e17c8; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in 0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in 053581d4657c6b5289c5de71a4828d313c005189; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in bbf15e83c37d9ac938b7c35c02b748fe54230010; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in 7443b16b6dd8889a3b9c5236a09e7c58f0d11dae; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in a0d9d9a3b41a1346c26af57aade6ba3f552fa171; From 771138920eafa399f68d3492c8a75dfeea23474b · fixed in dabb047c62668f280998e29117c55e41aabac336

  • Linux Linux

    3.15

  • KernelLinux

    From 3.15.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.5

References 8

git.kernel.org