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| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-06-10 18:41:44 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-10 19:14:18 -0700 |
| commit | 787d563b8642f35c561e439ebaf7ee5653437d05 (patch) | |
| tree | 64a1b8c21a9d8bcc655ce73d8e5133475d03baee /mm | |
| parent | 81c4f4d924d5d009b5ed785a3e22b18d0f7b831f (diff) | |
| download | lwn-787d563b8642f35c561e439ebaf7ee5653437d05.tar.gz lwn-787d563b8642f35c561e439ebaf7ee5653437d05.zip | |
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/debug_vm_pgtable.c | 6 |
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)))); |