Messages in this thread | | | From | "PaX Team" <> | Date | Mon, 04 May 2015 23:50:14 +0200 | Subject | Re: [PATCH v2 4/4] mm: Add debug code for SANITIZE_FREED_PAGES |
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On 4 May 2015 at 23:16, Anisse Astier wrote:
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index c29e3a0..ba8aa25 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -975,6 +975,31 @@ static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, > for (i = 0; i < (1 << order); i++) > clear_highpage(page + i); > #endif > +#ifdef CONFIG_SANITIZE_FREED_PAGES_DEBUG > + for (i = 0; i < (1 << order); i++) { > + struct page *p = page + i; > + int j; > + bool err = false; > + void *kaddr = kmap_atomic(p); > + > + for (j = 0; j < PAGE_SIZE; j++) {
did you mean to use memchr_inv(kaddr, 0, PAGE_SIZE) instead? ;)
> + if (((char *)kaddr)[j] != 0) { > + pr_err("page %p is not zero on alloc! %s\n", > + page_address(p), (gfp_flags & > + __GFP_ZERO) ? > + "fixing." : ""); > + if (gfp_flags & __GFP_ZERO) { > + err = true; > + kunmap_atomic(kaddr); > + clear_highpage(p); > + } > + break; > + } > + } > + if (!err) > + kunmap_atomic(kaddr); > + } > +#endif > > if (order && (gfp_flags & __GFP_COMP)) > prep_compound_page(page, order); > -- > 1.9.3 > >
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