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 29F62ECAAD2 for ; Sat, 27 Aug 2022 07:54:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232873AbiH0HyJ (ORCPT ); Sat, 27 Aug 2022 03:54:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230027AbiH0HyH (ORCPT ); Sat, 27 Aug 2022 03:54:07 -0400 Received: from mail-lf1-x134.google.com (mail-lf1-x134.google.com [IPv6:2a00:1450:4864:20::134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2872A2A40B for ; Sat, 27 Aug 2022 00:54:06 -0700 (PDT) Received: by mail-lf1-x134.google.com with SMTP id m2so942238lfp.11 for ; Sat, 27 Aug 2022 00:54:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc; bh=qMotkyLyfuzYTs8cUkh1HNEz4QJ/WmmadHhl7Jt1DmY=; b=DsJDBE3rKA03wvYjQRiUEIr3xrEZDQLItZKnjHG5ueTbZqsM4/yTZZTWSfr17GB/XQ Rwt3lz0euM8j92m94jSV5dCQQXtbbNqz7bpJOUTyVd+PQUf1IjRvHeONo22/T/e67uBU YqK47L4ic3p7StOG+SkJQih006KiRpqOBDqDHPSHwufIXL7uPkcOmqx88X9iUg7XFC7t bERTKkP/Y+BzuDAwIEO+ibVB4KNs0v8TDjAeuPBVzM5Kru/HMLm4+++ee30xDl8VfbSU k5bO9VxiySLN8kCQGU+/zGUFZP20wwd6dkxr+gH5sZ8wGXvtYdO4T/7TEoKsRo5ZLHr7 SpOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=qMotkyLyfuzYTs8cUkh1HNEz4QJ/WmmadHhl7Jt1DmY=; b=CcPah5HV6yVYntX6lCr/cmq2ZU9FqpiKuPV/o6z6s0RARB0BlRmxWAEfcP1BM2WI1c +y2yEVY3T560kORI/xgT7ORb2xoflBw0+4kJXUIBp1uRcWRumNPyRfqrqd/6An65aC/u s/2hebyCmnK1CDb1X04jFTTo0QyOlnVDifHwl3z1L8MoRybKb6FrmFPrStr2Fcq0dNRU hMoP1zerCsQYuI6heifpWVyDzaYMA5gHIL0qkevZeYTo0Cj6hwRicW208vch+Kqx9uAp rbfP5JK9xt1G/zAeEJkg1MSOdqVcHagwGMuGkdQDePkcTUC6V+Mm8uOO1I6EAxV6N3YR FGAA== X-Gm-Message-State: ACgBeo2lhw9XZi/uhPDqR8AhD+JMc5OZsohPjNPemBjrMdZgcXgjXVUx UD1CYAJ0v11imo9stCVItDyUsRRrouUAhRU8WHj7FWGCc0s= X-Google-Smtp-Source: AA6agR4LppQS/3wDkPRk2bMljwPa4EBqEZ8k6ssqzInCpLRmy+5MWuh4gDmQNV5tPqyqIsZXV5VEnX/4TohWZDDrAX4= X-Received: by 2002:a05:6512:68f:b0:492:cbb1:c4b2 with SMTP id t15-20020a056512068f00b00492cbb1c4b2mr3811823lfe.130.1661586844506; Sat, 27 Aug 2022 00:54:04 -0700 (PDT) MIME-Version: 1.0 References: <1661496048-26410-1-git-send-email-zhaoyang.huang@unisoc.com> In-Reply-To: From: Zhaoyang Huang Date: Sat, 27 Aug 2022 15:53:36 +0800 Message-ID: Subject: Re: [RFC PATCH] mm: introduce __GFP_TRACKLEAK to track in-kernel allocation To: "Vlastimil Babka (SUSE)" Cc: "zhaoyang.huang" , Andrew Morton , Catalin Marinas , "open list:MEMORY MANAGEMENT" , LKML , Ke Wang Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 26, 2022 at 7:49 PM Vlastimil Babka (SUSE) wrote: > > On 8/26/22 08:40, zhaoyang.huang wrote: > > From: Zhaoyang Huang > > > > Kthread and drivers could fetch memory via alloc_pages directly which make them > > hard to debug when leaking. Solve this by introducing __GFP_TRACELEAK and reuse > > kmemleak mechanism which unified most of kernel cosuming pages into kmemleak. > > Can you expand how exactly this is expected to be used? So you first have to > suspect some concrete allocation and add __GFP_TRACKLEAK to it? It could be used to investigate suspicious drivers or kthread which may introduce in-kernel leak during debug phase by enabling kmemleak. This can be done via page owner things now. I would like to unified it together with slab leak into kmemleak. > > > Signed-off-by: Zhaoyang Huang > > --- > > include/linux/gfp.h | 4 +++- > > include/linux/page-flags.h | 3 +++ > > mm/kmemleak.c | 2 +- > > mm/page_alloc.c | 6 ++++++ > > 4 files changed, 13 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > > index 2d2ccae..081ab54 100644 > > --- a/include/linux/gfp.h > > +++ b/include/linux/gfp.h > > @@ -68,6 +68,7 @@ > > #else > > #define ___GFP_NOLOCKDEP 0 > > #endif > > +#define ___GFP_TRACKLEAK 0x10000000u > > /* If the above are modified, __GFP_BITS_SHIFT may need updating */ > > > > /* > > @@ -259,12 +260,13 @@ > > #define __GFP_SKIP_ZERO ((__force gfp_t)___GFP_SKIP_ZERO) > > #define __GFP_SKIP_KASAN_UNPOISON ((__force gfp_t)___GFP_SKIP_KASAN_UNPOISON) > > #define __GFP_SKIP_KASAN_POISON ((__force gfp_t)___GFP_SKIP_KASAN_POISON) > > +#define __GFP_TRACKLEAK ((__force gfp_t)___GFP_TRACKLEAK) > > > > /* Disable lockdep for GFP context tracking */ > > #define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP) > > > > /* Room for N __GFP_FOO bits */ > > -#define __GFP_BITS_SHIFT (27 + IS_ENABLED(CONFIG_LOCKDEP)) > > +#define __GFP_BITS_SHIFT (28 + IS_ENABLED(CONFIG_LOCKDEP)) > > #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1)) > > > > /** > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > > index e66f7aa..ef0f814 100644 > > --- a/include/linux/page-flags.h > > +++ b/include/linux/page-flags.h > > @@ -942,6 +942,7 @@ static inline bool is_page_hwpoison(struct page *page) > > #define PG_offline 0x00000100 > > #define PG_table 0x00000200 > > #define PG_guard 0x00000400 > > +#define PG_trackleak 0x00000800 > > > > #define PageType(page, flag) \ > > ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) > > @@ -1012,6 +1013,8 @@ static inline int page_has_type(struct page *page) > > */ > > PAGE_TYPE_OPS(Guard, guard) > > > > +PAGE_TYPE_OPS(Trackleak, trackleak) > > + > > extern bool is_free_buddy_page(struct page *page); > > > > PAGEFLAG(Isolated, isolated, PF_ANY); > > diff --git a/mm/kmemleak.c b/mm/kmemleak.c > > index 422f28f..a182f5d 100644 > > --- a/mm/kmemleak.c > > +++ b/mm/kmemleak.c > > @@ -1471,7 +1471,7 @@ static void kmemleak_scan(void) > > if (page_zone(page) != zone) > > continue; > > /* only scan if page is in use */ > > - if (page_count(page) == 0 || PageReserved(page)) > > + if (page_count(page) == 0) > > continue; > > scan_block(page, page + 1, NULL); > > if (!(pfn & 63)) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index e008a3d..d8995c6 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -1361,6 +1361,8 @@ static __always_inline bool free_pages_prepare(struct page *page, > > page->mapping = NULL; > > if (memcg_kmem_enabled() && PageMemcgKmem(page)) > > __memcg_kmem_uncharge_page(page, order); > > + if (PageTrackleak(page)) > > + kmemleak_free(page); > > if (check_free) > > bad += check_free_page(page); > > if (bad) > > @@ -5444,6 +5446,10 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, > > __free_pages(page, order); > > page = NULL; > > } > > + if (gfp & __GFP_TRACKLEAK) { > > + kmemleak_alloc(page_address(page), PAGE_SIZE << order, 1, gfp & ~__GFP_TRACKLEAK); > > + __SetPageTrackleak(page); > > + } > > > > trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype); > > >