Commit 720da1e5 authored by Aneesh Kumar K.V (IBM)'s avatar Aneesh Kumar K.V (IBM) Committed by Andrew Morton
Browse files

mm/debug_vm_pgtable: fix BUG_ON with pud advanced test 

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: 27af67f3 ("powerpc/book3s64/mm: enable transparent pud hugepage")
Signed-off-by: default avatarAneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3a75cb05

mm/debug_vm_pgtable.c

+8 −0
Original line number Diff line number Diff line
@@ -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);