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Date: Mon, 04 May 2015 23:50:14 +0200 From: "PaX Team" <pageexec@...email.hu> To: Anisse Astier <anisse@...ier.eu> CC: Anisse Astier <anisse@...ier.eu>, Andrew Morton <akpm@...ux-foundation.org>, Mel Gorman <mgorman@...e.de>, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, David Rientjes <rientjes@...gle.com>, Alan Cox <gnomes@...rguk.ukuu.org.uk>, Linus Torvalds <torvalds@...ux-foundation.org>, Peter Zijlstra <peterz@...radead.org>, Brad Spengler <spender@...ecurity.net>, Kees Cook <keescook@...omium.org>, Andi Kleen <andi@...stfloor.org>, linux-mm@...ck.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2 4/4] mm: Add debug code for SANITIZE_FREED_PAGES 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 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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