In the Linux kernel, the following vulnerability has been resolved: bus: fsl-mc-bus: fix KASAN use-after-free in fsl_mc_bus_remove() In fsl_mc_bus_remove(), mc->root_mc_bus_dev->mc_io is passed to fsl_destroy_mc_io(). However, mc->root_mc_bus_dev is already freed in fsl_mc_device_remove(). Then reference to mc->root_mc_bus_dev->mc_io triggers KASAN use-after-free. To avoid the use-after-free, keep the reference to mc->root_mc_bus_dev->mc_io in a local variable and pass to fsl_destroy_mc_io(). This patch needs rework to apply to kernels older than v5.15.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.