From 53cdb27a933e4032934cbda0b447cfc9943c0eac Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 27 Jul 2008 10:35:54 +0100 Subject: [PATCH] [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: Russell King --- arch/arm/mm/fault-armv.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c index fbfa26058442..a8ec97b4752e 100644 --- a/arch/arm/mm/fault-armv.c +++ b/arch/arm/mm/fault-armv.c @@ -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; -- 2.20.1