From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D53AEECAAA1 for ; Fri, 28 Oct 2022 11:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229720AbiJ1L5h (ORCPT ); Fri, 28 Oct 2022 07:57:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229696AbiJ1L5e (ORCPT ); Fri, 28 Oct 2022 07:57:34 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A1871D2F53 for ; Fri, 28 Oct 2022 04:57:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 24CA6B829B5 for ; Fri, 28 Oct 2022 11:57:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A713C433C1; Fri, 28 Oct 2022 11:57:29 +0000 (UTC) Date: Fri, 28 Oct 2022 12:57:25 +0100 From: Catalin Marinas To: "zhaoyang.huang" Cc: Andrew Morton , Matthew Wilcox , Zhaoyang Huang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, ke.wang@unisoc.com, steve.kang@unisoc.com Subject: Re: [RFC PATCH] mm: track bad page via kmemleak Message-ID: References: <1663679468-16757-1-git-send-email-zhaoyang.huang@unisoc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1663679468-16757-1-git-send-email-zhaoyang.huang@unisoc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (sorry, I missed this last month when it was posted) On Tue, Sep 20, 2022 at 09:11:08PM +0800, zhaoyang.huang wrote: > From: Zhaoyang Huang > > Bad pages will failed go back to allocator and leaved as orphan pages, track > them down via kmemleak. > > Signed-off-by: Zhaoyang Huang > --- > mm/page_alloc.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index e5486d4..24f682e 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1408,7 +1408,7 @@ static __always_inline bool free_pages_prepare(struct page *page, > __memcg_kmem_uncharge_page(page, order); > reset_page_owner(page, order); > page_table_check_free(page, order); > - return false; > + goto err; > } > > /* > @@ -1442,7 +1442,7 @@ static __always_inline bool free_pages_prepare(struct page *page, > if (check_free) > bad += check_free_page(page); > if (bad) > - return false; > + goto err; > > page_cpupid_reset_last(page); > page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; > @@ -1486,6 +1486,10 @@ static __always_inline bool free_pages_prepare(struct page *page, > debug_pagealloc_unmap_pages(page, 1 << order); > > return true; > +err: > + kmemleak_alloc(page_address(page), PAGE_SIZE << order, 1, GFP_KERNEL); > + return false; > + > } What's the aim of this tracking? First of all, that's a HWPoison page and it should note be touched, so the min_count should be -1 otherwise kmemleak will try to read it for references to other objects. Now, if all you need is a list of the bad pages, I don't think that's kmemleak's job. Maybe add them to a list and expose it somewhere else via debugfs. -- Catalin