From d2a9510c0e39d06f5544075c13040407bdbf2803 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V (IBM)" Date: Mon, 29 Jan 2024 11:30:22 +0530 Subject: [PATCH] mm/debug_vm_pgtable: fix BUG_ON with pud advanced test commit 720da1e593b85a550593b415bf1d79a053133451 upstream. Architectures like powerpc add debug checks to ensure we find only devmap PUD pte entries. These debug checks are only done with CONFIG_DEBUG_VM. This patch marks the ptes used for PUD advanced test devmap pte entries so that we don't hit on debug checks on architecture like ppc64 as below. WARNING: CPU: 2 PID: 1 at arch/powerpc/mm/book3s64/radix_pgtable.c:1382 radix__pud_hugepage_update+0x38/0x138 .... NIP [c0000000000a7004] radix__pud_hugepage_update+0x38/0x138 LR [c0000000000a77a8] radix__pudp_huge_get_and_clear+0x28/0x60 Call Trace: [c000000004a2f950] [c000000004a2f9a0] 0xc000000004a2f9a0 (unreliable) [c000000004a2f980] [000d34c100000000] 0xd34c100000000 [c000000004a2f9a0] [c00000000206ba98] pud_advanced_tests+0x118/0x334 [c000000004a2fa40] [c00000000206db34] debug_vm_pgtable+0xcbc/0x1c48 [c000000004a2fc10] [c00000000000fd28] do_one_initcall+0x60/0x388 Also kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:202! .... NIP [c000000000096510] pudp_huge_get_and_clear_full+0x98/0x174 LR [c00000000206bb34] pud_advanced_tests+0x1b4/0x334 Call Trace: [c000000004a2f950] [000d34c100000000] 0xd34c100000000 (unreliable) [c000000004a2f9a0] [c00000000206bb34] pud_advanced_tests+0x1b4/0x334 [c000000004a2fa40] [c00000000206db34] debug_vm_pgtable+0xcbc/0x1c48 [c000000004a2fc10] [c00000000000fd28] do_one_initcall+0x60/0x388 Link: https://lkml.kernel.org/r/20240129060022.68044-1-aneesh.kumar@kernel.org Fixes: 27af67f35631 ("powerpc/book3s64/mm: enable transparent pud hugepage") Signed-off-by: Aneesh Kumar K.V (IBM) Cc: Anshuman Khandual Cc: Michael Ellerman Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/debug_vm_pgtable.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 48e329ea5ba3..13f0d1192707 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -362,6 +362,12 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args) vaddr &= HPAGE_PUD_MASK; pud = pfn_pud(args->pud_pfn, args->page_prot); + /* + * Some architectures have debug checks to make sure + * huge pud mapping are only found with devmap entries + * For now test with only devmap entries. + */ + pud = pud_mkdevmap(pud); set_pud_at(args->mm, vaddr, args->pudp, pud); flush_dcache_page(page); pudp_set_wrprotect(args->mm, vaddr, args->pudp); @@ -374,6 +380,7 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args) WARN_ON(!pud_none(pud)); #endif /* __PAGETABLE_PMD_FOLDED */ pud = pfn_pud(args->pud_pfn, args->page_prot); + pud = pud_mkdevmap(pud); pud = pud_wrprotect(pud); pud = pud_mkclean(pud); set_pud_at(args->mm, vaddr, args->pudp, pud); @@ -391,6 +398,7 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args) #endif /* __PAGETABLE_PMD_FOLDED */ pud = pfn_pud(args->pud_pfn, args->page_prot); + pud = pud_mkdevmap(pud); pud = pud_mkyoung(pud); set_pud_at(args->mm, vaddr, args->pudp, pud); flush_dcache_page(page);