mm/debug_vm_pgtable: fix kernel crash by checking for THP support
Architectures can have CONFIG_TRANSPARENT_HUGEPAGE enabled but no THP
support enabled based on platforms. For ex: with 4K PAGE_SIZE ppc64
supports THP only with radix translation.
This results in below crash when running with hash translation and 4K
PAGE_SIZE.
kernel BUG at arch/powerpc/include/asm/book3s/64/hash-4k.h:140!
cpu 0x61: Vector: 700 (Program Check) at [c000000ff948f860]
pc: debug_vm_pgtable+0x480/0x8b0
lr: debug_vm_pgtable+0x474/0x8b0
...
debug_vm_pgtable+0x374/0x8b0 (unreliable)
do_one_initcall+0x98/0x4f0
kernel_init_freeable+0x330/0x3fc
kernel_init+0x24/0x148
Check for THP support correctly
Link: http://lkml.kernel.org/r/20200608125252.407659-1-aneesh.kumar@linux.ibm.com
Fixes: 399145f9eb6c ("mm/debug: add tests validating architecture page table helpers")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed