| Message ID | 20200608125252.407659-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] mm/debug_vm_pgtable: Fix kernel crash by checking for THP support | expand |
On 06/08/2020 06:22 PM, Aneesh Kumar K.V wrote: > 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: c0000000018810f8: debug_vm_pgtable+0x480/0x8b0 > lr: c0000000018810ec: debug_vm_pgtable+0x474/0x8b0 > ... > [c000000ff948faf0] c000000001880fec debug_vm_pgtable+0x374/0x8b0 (unreliable) > [c000000ff948fbf0] c000000000011648 do_one_initcall+0x98/0x4f0 > [c000000ff948fcd0] c000000001843928 kernel_init_freeable+0x330/0x3fc > [c000000ff948fdb0] c0000000000122ac kernel_init+0x24/0x148 > [c000000ff948fe20] c00000000000cc44 ret_from_kernel_thread+0x5c/0x78 > > Check for THP support correctly > > Cc: anshuman.khandual@arm.com > Fixes: 399145f9eb6c ("mm/debug: add tests validating architecture page table helpers") > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > mm/debug_vm_pgtable.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index 188c18908964..df3a3a08f4f8 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -61,6 +61,9 @@ 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)))); > @@ -80,6 +83,9 @@ 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)))); > Builds with THP on arc, s390 and runs with THP on x86 and arm64 platforms. Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 188c18908964..df3a3a08f4f8 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -61,6 +61,9 @@ 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)))); @@ -80,6 +83,9 @@ 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))));
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: c0000000018810f8: debug_vm_pgtable+0x480/0x8b0 lr: c0000000018810ec: debug_vm_pgtable+0x474/0x8b0 ... [c000000ff948faf0] c000000001880fec debug_vm_pgtable+0x374/0x8b0 (unreliable) [c000000ff948fbf0] c000000000011648 do_one_initcall+0x98/0x4f0 [c000000ff948fcd0] c000000001843928 kernel_init_freeable+0x330/0x3fc [c000000ff948fdb0] c0000000000122ac kernel_init+0x24/0x148 [c000000ff948fe20] c00000000000cc44 ret_from_kernel_thread+0x5c/0x78 Check for THP support correctly Cc: anshuman.khandual@arm.com Fixes: 399145f9eb6c ("mm/debug: add tests validating architecture page table helpers") Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- mm/debug_vm_pgtable.c | 6 ++++++ 1 file changed, 6 insertions(+)