2024-12-28 09:46:06
Linux
PUBLISHED
In the Linux kernel, the following vulnerability has been resolved:
powerpc/fadump: Move fadump_cma_init to setup_arch() after initmem_init()
During early init CMA_MIN_ALIGNMENT_BYTES can be PAGE_SIZE,
since pageblock_order is still zero and it gets initialized
later during initmem_init() e.g.
setup_arch() -> initmem_init() -> sparse_init() -> set_pageblock_order()
One such use case where this causes issue is -
early_setup() -> early_init_devtree() -> fadump_reserve_mem() -> fadump_cma_init()
This causes CMA memory alignment check to be bypassed in
cma_init_reserved_mem(). Then later cma_activate_area() can hit
a VM_BUG_ON_PAGE(pfn & ((1 << order) - 1)) if the reserved memory
area was not pageblock_order aligned.
Fix it by moving the fadump_cma_init() after initmem_init(),
where other such cma reservations also gets called.