Commit 401035d5 authored Oct 15, 2020 by Aneesh Kumar K.V Committed by Linus Torvalds Oct 16, 2020

mm/debug_vm_pgtable: avoid none pte in pte_clear_test

pte_clear_tests operate on an existing pte entry.  Make sure that is not a
none pte entry.

[aneesh.kumar@linux.ibm.com: avoid kernel crash with riscv]
  Link: https://lkml.kernel.org/r/20201015033206.140550-1-aneesh.kumar@linux.ibm.com



Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: https://lkml.kernel.org/r/20200902114222.181353-14-aneesh.kumar@linux.ibm.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 2b1dd67a

mm/debug_vm_pgtable.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -540,12 +540,15 @@ static void __init pgd_populate_tests(struct mm_struct mm, pgd_t pgdp,
		#endif /* PAGETABLE_P4D_FOLDED */

		static void __init pte_clear_tests(struct mm_struct mm, pte_t ptep,
		unsigned long vaddr)
		unsigned long pfn, unsigned long vaddr,
		pgprot_t prot)
		{
		pte_t pte = ptep_get(ptep);
		pte_t pte = pfn_pte(pfn, prot);

		pr_debug("Validating PTE clear\n");
		#ifndef CONFIG_RISCV
		pte = __pte(pte_val(pte) \| RANDOM_ORVALUE);
		#endif
		set_pte_at(mm, vaddr, ptep, pte);
		barrier();
		pte_clear(mm, vaddr, ptep);
		@@ -996,7 +999,7 @@ static int __init debug_vm_pgtable(void)

		ptl = pte_lockptr(mm, pmdp);
		spin_lock(ptl);
		pte_clear_tests(mm, ptep, vaddr);
		pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
		pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
		pte_unmap_unlock(ptep, ptl);

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