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authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>2020-06-10 18:41:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-10 19:14:18 -0700
commit787d563b8642f35c561e439ebaf7ee5653437d05 (patch)
tree64a1b8c21a9d8bcc655ce73d8e5133475d03baee
parent81c4f4d924d5d009b5ed785a3e22b18d0f7b831f (diff)
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>
-rw-r--r--mm/debug_vm_pgtable.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 9ec59c38d6a2..e45623016aea 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -60,6 +60,9 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
{
pmd_t pmd = pfn_pmd(pfn, prot);
+ if (!has_transparent_hugepage())
+ return;
+
WARN_ON(!pmd_same(pmd, pmd));
WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd))));
WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd))));
@@ -79,6 +82,9 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
{
pud_t pud = pfn_pud(pfn, prot);
+ if (!has_transparent_hugepage())
+ return;
+
WARN_ON(!pud_same(pud, pud));
WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud))));
WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud))));