In the Linux kernel, the following vulnerability has been resolved:

xen: unexport __init-annotated xen_xlate_map_ballooned_pages()

EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization. Hence, modules cannot
use symbols annotated __init. The access to a freed symbol may end up
with kernel panic.

modpost used to detect it, but it has been broken for a decade.

Recently, I fixed modpost so it started to warn it again, then this
showed up in linux-next builds.

There are two ways to fix it:

  - Remove __init
  - Remove EXPORT_SYMBOL

I chose the latter for this case because none of the in-tree call-sites
(arch/arm/xen/enlighten.c, arch/x86/xen/grant-table.c) is compiled as
modular.

https://git.kernel.org/stable/c/0ddb4334f4136cd5c84885032894663a4d57928d

https://git.kernel.org/stable/c/29a9935a90dd32b89d04e249e0a948cb4949e7af

https://git.kernel.org/stable/c/40e6078fcf186b4f452abcbffcb004e28d750395

https://git.kernel.org/stable/c/b43387364d8291190fd4ea1322b65c337802baa2

https://git.kernel.org/stable/c/b49c884146e20314808c9420640b26876ff55c80

https://git.kernel.org/stable/c/be9581f4fda795aa0e18cdc333efc1e447e1a55c

https://git.kernel.org/stable/c/c0d076419136a7528abc1831847099400f61d60f

https://git.kernel.org/stable/c/dbac14a5a05ff8e1ce7c0da0e1f520ce39ec62ea

https://git.kernel.org/stable/c/f319c9b45b351019349cc779ce6721ebc211245c