Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
media: pwc: Drain fill_buf on start_streaming() failure
pwc_isoc_init() submits its isochronous URBs with usb_submit_urb(.., GFP_KERNEL) in a loop. After the first URB is submitted, its completion handler pwc_isoc_handler() can run on another CPU before the loop finishes:
start_streaming() pwc_isoc_init() usb_submit_urb(urbs[0], GFP_KERNEL) pwc_isoc_handler(urbs[0]) pdev->fill_buf = pwc_get_next_fill_buf(pdev) usb_submit_urb(urbs[i>0], ..) -> fails pwc_isoc_cleanup(pdev) /* kills URBs */ return ret; pwc_cleanup_queued_bufs(pdev, VB2_BUF_STATE_QUEUED)
pwc_get_next_fill_buf() detaches a buffer from pdev->queued_bufs and stores it in pdev->fill_buf. The error path in start_streaming() only drains pdev->queued_bufs, so the buffer parked in pdev->fill_buf is leaked. vb2_start_streaming() then triggers WARN_ON(owned_by_drv_count).
stop_streaming() already handles this since commit 80b0963e1698 ("[media] pwc: fix WARN_ON"), which added the fill_buf drain in the teardown path but not in the start_streaming() error path. Mirror that handling on failure so start_streaming() returns with no buffer owned by the driver.
Issue identified by automated review of the INV-003 series at https://sashiko.dev/
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.19.0 (+17 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 12 | Released |
43 kernels
|
| Debian 13 | Released |
14 kernels
|
| Oracle Linux 8 UEK 7 | Released |
112 kernels
|
| Oracle Linux 9 UEK 7 | Released |
112 kernels
|
| Proxmox VE 7 5.15 | In Rollout |
47 kernels
|
| Ubuntu 20.04 HWE AWS | In Rollout |
57 kernels
|
| Ubuntu 22.04 | Released |
102 kernels
|
| Ubuntu 22.04 AWS | Released |
93 kernels
|
| Ubuntu 22.04 Azure | Will Not Fix |
83 kernels
|
| Ubuntu 24.04 | Planned | — |
| Ubuntu 24.04 AWS | Planned | — |
| Ubuntu 26.04 | Will Not Fix | — |