fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info
At a glance
Severity
HIGH 7.8
EPSS
EPSS 0.13 % · percentile 3 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Undergoing Analysis
Description
In the Linux kernel, the following vulnerability has been resolved:
fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info
Hold state of deferred I/O in struct fb_deferred_io_state. Allocate an
instance as part of initializing deferred I/O and remove it only after
the final mapping has been closed. If the fb_info and the contained
deferred I/O meanwhile goes away, clear struct fb_deferred_io_state.info
to invalidate the mapping. Any access will then result in a SIGBUS
signal.
Fixes a long-standing problem, where a device hot-unplug happens while
user space still has an active mapping of the graphics memory. The hot-
unplug frees the instance of struct fb_info. Accessing the memory will
operate on undefined state.
