Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751507AbbEDVw3 (ORCPT ); Mon, 4 May 2015 17:52:29 -0400 Received: from r00tworld.com ([212.85.137.150]:52259 "EHLO r00tworld.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbbEDVwU (ORCPT ); Mon, 4 May 2015 17:52:20 -0400 From: "PaX Team" To: Anisse Astier Date: Mon, 04 May 2015 23:50:14 +0200 MIME-Version: 1.0 Subject: Re: [PATCH v2 4/4] mm: Add debug code for SANITIZE_FREED_PAGES Reply-to: pageexec@freemail.hu CC: Anisse Astier , Andrew Morton , Mel Gorman , "Kirill A. Shutemov" , David Rientjes , Alan Cox , Linus Torvalds , Peter Zijlstra , Brad Spengler , Kees Cook , Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org Message-ID: <5547E996.16766.8008534@pageexec.freemail.hu> In-reply-to: <1430774218-5311-5-git-send-email-anisse@astier.eu> References: <1430774218-5311-1-git-send-email-anisse@astier.eu>, <1430774218-5311-5-git-send-email-anisse@astier.eu> X-mailer: Pegasus Mail for Windows (4.70) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.12 (r00tworld.com [212.85.137.150]); Mon, 04 May 2015 23:50:31 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1399 Lines: 53 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/