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

s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()

There is no support for HWPOISON, MEMORY_FAILURE, or ARCH_HAS_COPY_MC on
s390. Therefore we do not expect to see VM_FAULT_HWPOISON in
do_exception().

However, since commit af19487f00f3 ("mm: make PTE_MARKER_SWAPIN_ERROR more
general"), it is possible to see VM_FAULT_HWPOISON in combination with
PTE_MARKER_POISONED, even on architectures that do not support HWPOISON
otherwise. In this case, we will end up on the BUG() in do_exception().

Fix this by treating VM_FAULT_HWPOISON the same as VM_FAULT_SIGBUS, similar
to x86 when MEMORY_FAILURE is not configured. Also print unexpected fault
flags, for easier debugging.

Note that VM_FAULT_HWPOISON_LARGE is not expected, because s390 cannot
support swap entries on other levels than PTE level.

kernel.org https://git.kernel.org/stable/c/9e13767ccefdc4f8aa92514b592b60f6b54882ff [No types assigned]

kernel.org https://git.kernel.org/stable/c/a3aefb871222a9880602d1a44a558177b4143e3b [No types assigned]

kernel.org https://git.kernel.org/stable/c/df39038cd89525d465c2c8827eb64116873f141a [No types assigned]