CVE-2022-50332
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-15

Last updated on: 2025-12-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: video/aperture: Call sysfb_disable() before removing PCI devices Call sysfb_disable() from aperture_remove_conflicting_pci_devices() before removing PCI devices. Without, simpledrm can still bind to simple-framebuffer devices after the hardware driver has taken over the hardware. Both drivers interfere with each other and results are undefined. Reported modesetting errors [1] are shown below. ---- snap ---- rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 13-.... } 7 jiffies s: 165 root: 0x2000/. rcu: blocking rcu_node structures (internal RCU debug): Task dump for CPU 13: task:X state:R running task stack: 0 pid: 4242 ppid: 4228 flags:0x00000008 Call Trace: <TASK> ? commit_tail+0xd7/0x130 ? drm_atomic_helper_commit+0x126/0x150 ? drm_atomic_commit+0xa4/0xe0 ? drm_plane_get_damage_clips.cold+0x1c/0x1c ? drm_atomic_helper_dirtyfb+0x19e/0x280 ? drm_mode_dirtyfb_ioctl+0x10f/0x1e0 ? drm_mode_getfb2_ioctl+0x2d0/0x2d0 ? drm_ioctl_kernel+0xc4/0x150 ? drm_ioctl+0x246/0x3f0 ? drm_mode_getfb2_ioctl+0x2d0/0x2d0 ? __x64_sys_ioctl+0x91/0xd0 ? do_syscall_64+0x60/0xd0 ? entry_SYSCALL_64_after_hwframe+0x4b/0xb5 </TASK> ... rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 13-.... } 30 jiffies s: 169 root: 0x2000/. rcu: blocking rcu_node structures (internal RCU debug): Task dump for CPU 13: task:X state:R running task stack: 0 pid: 4242 ppid: 4228 flags:0x0000400e Call Trace: <TASK> ? memcpy_toio+0x76/0xc0 ? memcpy_toio+0x1b/0xc0 ? drm_fb_memcpy_toio+0x76/0xb0 ? drm_fb_blit_toio+0x75/0x2b0 ? simpledrm_simple_display_pipe_update+0x132/0x150 ? drm_atomic_helper_commit_planes+0xb6/0x230 ? drm_atomic_helper_commit_tail+0x44/0x80 ? commit_tail+0xd7/0x130 ? drm_atomic_helper_commit+0x126/0x150 ? drm_atomic_commit+0xa4/0xe0 ? drm_plane_get_damage_clips.cold+0x1c/0x1c ? drm_atomic_helper_dirtyfb+0x19e/0x280 ? drm_mode_dirtyfb_ioctl+0x10f/0x1e0 ? drm_mode_getfb2_ioctl+0x2d0/0x2d0 ? drm_ioctl_kernel+0xc4/0x150 ? drm_ioctl+0x246/0x3f0 ? drm_mode_getfb2_ioctl+0x2d0/0x2d0 ? __x64_sys_ioctl+0x91/0xd0 ? do_syscall_64+0x60/0xd0 ? entry_SYSCALL_64_after_hwframe+0x4b/0xb5 </TASK> The problem was added by commit 5e0137612430 ("video/aperture: Disable and unregister sysfb devices via aperture helpers") to v6.0.3 and does not exist in the mainline branch. The mainline commit 5e0137612430 ("video/aperture: Disable and unregister sysfb devices via aperture helpers") has been backported from v6.0-rc1 to stable v6.0.3 from a larger patch series [2] that reworks fbdev framebuffer ownership. The backport misses a change to aperture_remove_conflicting_pci_devices(). Mainline itself is fine, because the function does not exist there as a result of the patch series. Instead of backporting the whole series, fix the additional function.
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Meta Information
Published
2025-09-15
Last Modified
2025-12-04
Generated
2026-05-07
AI Q&A
2025-09-15
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel From 6.0.3 (inc) to 6.0.6 (exc)
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Exploitability
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CWE ID Description
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's video/aperture subsystem where the function sysfb_disable() was not called before removing PCI devices. Without this call, the simpledrm driver can still bind to simple-framebuffer devices after the hardware driver has taken control of the hardware. This causes interference between the two drivers, leading to undefined behavior and reported modesetting errors such as CPU stalls and task blocking.


How can this vulnerability impact me? :

The vulnerability can cause system instability due to interference between the simpledrm and hardware drivers managing the framebuffer devices. This may result in modesetting errors, CPU stalls, and unpredictable system behavior, potentially affecting the reliability and performance of graphics operations on affected Linux systems.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by observing reported modesetting errors and RCU stalls related to simpledrm and simple-framebuffer devices interfering with each other. You can check system logs (e.g., using 'dmesg' or 'journalctl') for messages indicating rcu_sched detected expedited stalls and drm-related call traces as shown in the description. Specific commands to look for these errors include: 'dmesg | grep rcu_sched' and 'dmesg | grep drm'.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, ensure that your Linux kernel is updated to a version that includes the fix, specifically version 6.0.3 or later where the patch disabling and unregistering sysfb devices via aperture helpers is applied. This prevents simpledrm from binding to simple-framebuffer devices after the hardware driver takes over, avoiding interference. If updating is not immediately possible, avoid removing PCI devices without calling sysfb_disable() to prevent the conflict.


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