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Commit 53cdb27a authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[ARM] Fix shared mmap when more than two maps of the same file exist 



The shared mmap code works fine for the test case, which only checked
for two shared maps of the same file.  However, three shared maps
result in one mapping remaining cached, resulting in stale data being
visible via that mapping.  Fix this.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent daf93dd5

arch/arm/mm/fault-armv.c

+7 −3
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address) 
	pgd_t *pgd;

	pmd_t *pmd;

	pte_t *pte, entry;

	int ret = 0;

	int ret;



	pgd = pgd_offset(vma->vm_mm, address);

	if (pgd_none(*pgd))
@@ -54,16 +54,20 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address) 
	pte = pte_offset_map(pmd, address);

	entry = *pte;



	/*

	 * If this page is present, it's actually being shared.

	 */

	ret = pte_present(entry);



	/*

	 * If this page isn't present, or is already setup to

	 * fault (ie, is old), we can safely ignore any issues.

	 */

	if (pte_present(entry) && pte_val(entry) & shared_pte_mask) {

	if (ret && pte_val(entry) & shared_pte_mask) {

		flush_cache_page(vma, address, pte_pfn(entry));

		pte_val(entry) &= ~shared_pte_mask;

		set_pte_at(vma->vm_mm, address, pte, entry);

		flush_tlb_page(vma, address);

		ret = 1;

	}

	pte_unmap(pte);

	return ret;