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 0C7CBC433F5 for ; Fri, 27 May 2022 11:17:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351252AbiE0LRw (ORCPT ); Fri, 27 May 2022 07:17:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232837AbiE0LRu (ORCPT ); Fri, 27 May 2022 07:17:50 -0400 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 640B3122B61 for ; Fri, 27 May 2022 04:17:48 -0700 (PDT) X-UUID: edc55d0acafa4a9c981f9c0f8070a9de-20220527 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.5,REQID:d9dbc11a-506e-45c6-a732-5ef9c533a063,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACTI ON:release,TS:0 X-CID-META: VersionHash:2a19b09,CLOUDID:381bbc47-4fb1-496b-8f1d-39e733fed1ea,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:0,File:nil ,QS:0,BEC:nil X-UUID: edc55d0acafa4a9c981f9c0f8070a9de-20220527 Received: from mtkmbs10n2.mediatek.inc [(172.21.101.183)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 135672329; Fri, 27 May 2022 19:17:43 +0800 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by mtkmbs11n2.mediatek.inc (172.21.101.187) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.3; Fri, 27 May 2022 19:17:42 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Fri, 27 May 2022 19:17:42 +0800 Message-ID: <3b1542b95a3d322b798bf212b22c6c3567a76c13.camel@mediatek.com> Subject: Re: [PATCH] mm: kmemleak: Skip check in kmemleak_*_phys when pfn bound is not ready From: Yee Lee To: patrick wang CC: , , , , , Catalin Marinas , Andrew Morton , Matthias Brugger , "open list:MEMORY MANAGEMENT" , "moderated list:ARM/Mediatek SoC support" , "moderated list:ARM/Mediatek SoC support" Date: Fri, 27 May 2022 19:17:42 +0800 In-Reply-To: References: <20220527032504.30341-1-yee.lee@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2022-05-27 at 18:20 +0800, patrick wang wrote: > On Fri, May 27, 2022 at 11:25 AM wrote: > > > > From: Yee Lee > > > > In some archs (arm64), memblock allocates memory in boot time when > > the pfn boundary (max_pfn/min_pfn) is not ready. The lowmen checks > > in > > kmemleak_*_phys() drop those blocks and cause some false leak > > alarms > > on common kernel objects. > > If I understand correctly, if those blocks are dropped, they will > not be added as kmemleak objects. So how could this affect > other objects? > > Thanks, > Patrick Yes, in fact, memblock needs those areas never reported as leaks and add them as grey blocks. More detailed comments can be found inside memblock_alloc_range_nid. > > > > > Kmemleak output: (Qemu/arm64) > > unreferenced object 0xffff0000c0170a00 (size 128): > > comm "swapper/0", pid 1, jiffies 4294892404 (age 126.208s) > > hex dump (first 32 bytes): > > 62 61 73 65 00 00 00 00 00 00 00 00 00 00 00 > > 00 base............ > > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > 00 ................ > > backtrace: > > [<(____ptrval____)>] __kmalloc_track_caller+0x1b0/0x2e4 > > [<(____ptrval____)>] kstrdup_const+0x8c/0xc4 > > [<(____ptrval____)>] kvasprintf_const+0xbc/0xec > > [<(____ptrval____)>] kobject_set_name_vargs+0x58/0xe4 > > [<(____ptrval____)>] kobject_add+0x84/0x100 > > [<(____ptrval____)>] __of_attach_node_sysfs+0x78/0xec > > [<(____ptrval____)>] of_core_init+0x68/0x104 > > [<(____ptrval____)>] driver_init+0x28/0x48 > > [<(____ptrval____)>] do_basic_setup+0x14/0x28 > > [<(____ptrval____)>] kernel_init_freeable+0x110/0x178 > > [<(____ptrval____)>] kernel_init+0x20/0x1a0 > > [<(____ptrval____)>] ret_from_fork+0x10/0x20 > > > > This patch relaxs the boundary checking in kmemleak_*_phys api > > if max_low_pfn is uninitialzed. > > > > Fixes: 23c2d4 (mm: kmemleak: take a full lowmem check in > > kmemleak_*_phy) > > Signed-off-by: Yee Lee > > --- > > mm/kmemleak.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/mm/kmemleak.c b/mm/kmemleak.c > > index a182f5ddaf68..6b2af544aa0f 100644 > > --- a/mm/kmemleak.c > > +++ b/mm/kmemleak.c > > @@ -1132,7 +1132,7 @@ EXPORT_SYMBOL(kmemleak_no_scan); > > void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int > > min_count, > > gfp_t gfp) > > { > > - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < > > max_low_pfn) > > + if (!max_low_pfn || (PHYS_PFN(phys) >= min_low_pfn && > > PHYS_PFN(phys) < max_low_pfn)) > > kmemleak_alloc(__va(phys), size, min_count, gfp); > > } > > EXPORT_SYMBOL(kmemleak_alloc_phys); > > @@ -1146,7 +1146,7 @@ EXPORT_SYMBOL(kmemleak_alloc_phys); > > */ > > void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size) > > { > > - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < > > max_low_pfn) > > + if (!max_low_pfn || (PHYS_PFN(phys) >= min_low_pfn && > > PHYS_PFN(phys) < max_low_pfn)) > > kmemleak_free_part(__va(phys), size); > > } > > EXPORT_SYMBOL(kmemleak_free_part_phys); > > @@ -1158,7 +1158,7 @@ EXPORT_SYMBOL(kmemleak_free_part_phys); > > */ > > void __ref kmemleak_not_leak_phys(phys_addr_t phys) > > { > > - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < > > max_low_pfn) > > + if (!max_low_pfn || (PHYS_PFN(phys) >= min_low_pfn && > > PHYS_PFN(phys) < max_low_pfn)) > > kmemleak_not_leak(__va(phys)); > > } > > EXPORT_SYMBOL(kmemleak_not_leak_phys); > > @@ -1170,7 +1170,7 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys); > > */ > > void __ref kmemleak_ignore_phys(phys_addr_t phys) > > { > > - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < > > max_low_pfn) > > + if (!max_low_pfn || (PHYS_PFN(phys) >= min_low_pfn && > > PHYS_PFN(phys) < max_low_pfn)) > > kmemleak_ignore(__va(phys)); > > } > > EXPORT_SYMBOL(kmemleak_ignore_phys); > > -- > > 2.18.0 > >