ARM: 6255/1: Workaround infinity loop in handling of translation faults (33a9c41b) · Commits · 戴 / test

On ARM one Linux PGD entry contains two hardware entries (see page tables layout in pgtable.h). We normally guarantee that we always fill both L1 entries. But create_mapping() doesn't follow the rule. It can create inidividual L1 entries, so here we have to call pmd_none() check in do_translation_fault() for the entry really corresponded to address, not for the first of pair. Signed-off-by:

Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by:

Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/fault.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -413,7 +413,16 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
		pmd_k = pmd_offset(pgd_k, addr);
		pmd = pmd_offset(pgd, addr);

		if (pmd_none(*pmd_k))
		/*
		* On ARM one Linux PGD entry contains two hardware entries (see page
		* tables layout in pgtable.h). We normally guarantee that we always
		* fill both L1 entries. But create_mapping() doesn't follow the rule.
		* It can create inidividual L1 entries, so here we have to call
		* pmd_none() check for the entry really corresponded to address, not
		* for the first of pair.
		*/
		index = (addr >> SECTION_SHIFT) & 1;
		if (pmd_none(pmd_k[index]))
		goto bad_area;

		copy_pmd(pmd, pmd_k);

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