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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B05C0C4740A for ; Mon, 7 Oct 2019 08:02:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D09E2133F for ; Mon, 7 Oct 2019 08:02:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YKX80zqK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727438AbfJGICV (ORCPT ); Mon, 7 Oct 2019 04:02:21 -0400 Received: from mail-lf1-f66.google.com ([209.85.167.66]:33239 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726889AbfJGICV (ORCPT ); Mon, 7 Oct 2019 04:02:21 -0400 Received: by mail-lf1-f66.google.com with SMTP id y127so8577385lfc.0 for ; Mon, 07 Oct 2019 01:02:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=dD+rwXY/nYOWBAq4CYmtKPehya96hW8MC3evJji/Yec=; b=YKX80zqK9BnbAJeglBJloTgyzdIqVvyc8qZo+JZ3ztomB/oSL2bR0cdAskjskLkt7W V9UDSFbbXRmNPZ33L0D1wU65+1nH2oAp6y8pZPleWLLZCun4eCXakWs8mS4RWb6C/ker JW+RSQDoEOrmeywy1usBuMsnExaiprDjukREATWF2vWVXQ4YtCLFHEdtes6ohAKHQKtf q+L1AWmRm9SfD1K0Iykdhz4e4rb4yRZA5P2ouhEARMWWMz9rxMUok+sY7y4FKuV75C8t 0xbcdLUk2/EkgOxlDRwB9q8u6xQVYUzdRCjrlrEYJnWvIf4sPd888A9bqnH++YKjN+jF dmZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=dD+rwXY/nYOWBAq4CYmtKPehya96hW8MC3evJji/Yec=; b=cntKYFheDOTnp/afZyWsj2L5m9nM2I0mmQtMa74iWbt/Ijl/1f5JNT05QTAPWkZ7/d F3/VRVbqrxzaUBubfymHr3yVhaF34qTHvc5fmTr26RQbnWwjNNntytSfs6Oi+JuhEu+B KvaZtfd8pU1ZYe5Wpi5K6sQlLN4vNqVzvEUlWFOXEN3hvNxOjZgsSJifg3KPuwWJgd5P b938M27LUL6CYsEf2+u0hLjq8w1N/B2k4p+6nNtc/PZrES7VT29lRCkU78Z1I4nJZqQI Iufp3YYKJznJTED6rRoo7HAf4aOQz7X4Y0Z48ZIPh6zJw9/O5+XTo5T92NaaoauzNOR/ Hf3A== X-Gm-Message-State: APjAAAXxzB/6v4YBwIHtYlJOp0NTeIJhC1GPM3psRj+trgvIRzhqpoQ6 MMFQjBawzkRUjXqcf/VghYs= X-Google-Smtp-Source: APXvYqyYVjjEk4t55bliwrB5kqrPSByuGmBtIo84DXhVvDur8OAwQWGVhoAdoOt78OMFi9yojAsMng== X-Received: by 2002:ac2:4a8f:: with SMTP id l15mr16241092lfp.21.1570435338163; Mon, 07 Oct 2019 01:02:18 -0700 (PDT) Received: from pc636 (h5ef52e31.seluork.dyn.perspektivbredband.net. [94.245.46.49]) by smtp.gmail.com with ESMTPSA id f21sm3218392lfm.90.2019.10.07.01.02.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Oct 2019 01:02:17 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 7 Oct 2019 10:02:09 +0200 To: Daniel Axtens Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, x86@kernel.org, aryabinin@virtuozzo.com, glider@google.com, luto@kernel.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, dvyukov@google.com, christophe.leroy@c-s.fr, linuxppc-dev@lists.ozlabs.org, gor@linux.ibm.com Subject: Re: [PATCH v8 1/5] kasan: support backing vmalloc space with real shadow memory Message-ID: <20191007080209.GA22997@pc636> References: <20191001065834.8880-1-dja@axtens.net> <20191001065834.8880-2-dja@axtens.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191001065834.8880-2-dja@axtens.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index a3c70e275f4e..9fb7a16f42ae 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -690,8 +690,19 @@ merge_or_add_vmap_area(struct vmap_area *va, > struct list_head *next; > struct rb_node **link; > struct rb_node *parent; > + unsigned long orig_start, orig_end; > bool merged = false; > > + /* > + * To manage KASAN vmalloc memory usage, we use this opportunity to > + * clean up the shadow memory allocated to back this allocation. > + * Because a vmalloc shadow page covers several pages, the start or end > + * of an allocation might not align with a shadow page. Use the merging > + * opportunities to try to extend the region we can release. > + */ > + orig_start = va->va_start; > + orig_end = va->va_end; > + > /* > * Find a place in the tree where VA potentially will be > * inserted, unless it is merged with its sibling/siblings. > @@ -741,6 +752,10 @@ merge_or_add_vmap_area(struct vmap_area *va, > if (sibling->va_end == va->va_start) { > sibling->va_end = va->va_end; > > + kasan_release_vmalloc(orig_start, orig_end, > + sibling->va_start, > + sibling->va_end); > + > /* Check and update the tree if needed. */ > augment_tree_propagate_from(sibling); > > @@ -754,6 +769,8 @@ merge_or_add_vmap_area(struct vmap_area *va, > } > > insert: > + kasan_release_vmalloc(orig_start, orig_end, va->va_start, va->va_end); > + > if (!merged) { > link_va(va, root, parent, link, head); > augment_tree_propagate_from(va); Hello, Daniel. Looking at it one more, i think above part of code is a bit wrong and should be separated from merge_or_add_vmap_area() logic. The reason is to keep it simple and do only what it is supposed to do: merging or adding. Also the kasan_release_vmalloc() gets called twice there and looks like a duplication. Apart of that, merge_or_add_vmap_area() can be called via recovery path when vmap/vmaps is/are not even setup. See percpu allocator. I guess your part could be moved directly to the __purge_vmap_area_lazy() where all vmaps are lazily freed. To do so, we also need to modify merge_or_add_vmap_area() to return merged area: diff --git a/mm/vmalloc.c b/mm/vmalloc.c index e92ff5f7dd8b..fecde4312d68 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -683,7 +683,7 @@ insert_vmap_area_augment(struct vmap_area *va, * free area is inserted. If VA has been merged, it is * freed. */ -static __always_inline void +static __always_inline struct vmap_area * merge_or_add_vmap_area(struct vmap_area *va, struct rb_root *root, struct list_head *head) { @@ -750,7 +750,10 @@ merge_or_add_vmap_area(struct vmap_area *va, /* Free vmap_area object. */ kmem_cache_free(vmap_area_cachep, va); - return; + + /* Point to the new merged area. */ + va = sibling; + merged = true; } } @@ -759,6 +762,8 @@ merge_or_add_vmap_area(struct vmap_area *va, link_va(va, root, parent, link, head); augment_tree_propagate_from(va); } + + return va; } static __always_inline bool @@ -1172,7 +1177,7 @@ static void __free_vmap_area(struct vmap_area *va) /* * Merge VA with its neighbors, otherwise just add it. */ - merge_or_add_vmap_area(va, + (void) merge_or_add_vmap_area(va, &free_vmap_area_root, &free_vmap_area_list); } @@ -1279,15 +1284,20 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) spin_lock(&vmap_area_lock); llist_for_each_entry_safe(va, n_va, valist, purge_list) { unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT; + unsigned long orig_start = va->va_start; + unsigned long orig_end = va->va_end; /* * Finally insert or merge lazily-freed area. It is * detached and there is no need to "unlink" it from * anything. */ - merge_or_add_vmap_area(va, + va = merge_or_add_vmap_area(va, &free_vmap_area_root, &free_vmap_area_list); + kasan_release_vmalloc(orig_start, + orig_end, va->va_start, va->va_end); + atomic_long_sub(nr, &vmap_lazy_nr); if (atomic_long_read(&vmap_lazy_nr) < resched_threshold) -- Vlad Rezki 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 X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB435C4740A for ; Mon, 7 Oct 2019 08:04:19 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D93152133F for ; Mon, 7 Oct 2019 08:04:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YKX80zqK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D93152133F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46mtKr2TcgzDqMH for ; Mon, 7 Oct 2019 19:04:16 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=gmail.com (client-ip=2a00:1450:4864:20::143; helo=mail-lf1-x143.google.com; envelope-from=urezki@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="YKX80zqK"; dkim-atps=neutral Received: from mail-lf1-x143.google.com (mail-lf1-x143.google.com [IPv6:2a00:1450:4864:20::143]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46mtHm29DNzDq6l for ; Mon, 7 Oct 2019 19:02:25 +1100 (AEDT) Received: by mail-lf1-x143.google.com with SMTP id r2so8535992lfn.8 for ; Mon, 07 Oct 2019 01:02:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=dD+rwXY/nYOWBAq4CYmtKPehya96hW8MC3evJji/Yec=; b=YKX80zqK9BnbAJeglBJloTgyzdIqVvyc8qZo+JZ3ztomB/oSL2bR0cdAskjskLkt7W V9UDSFbbXRmNPZ33L0D1wU65+1nH2oAp6y8pZPleWLLZCun4eCXakWs8mS4RWb6C/ker JW+RSQDoEOrmeywy1usBuMsnExaiprDjukREATWF2vWVXQ4YtCLFHEdtes6ohAKHQKtf q+L1AWmRm9SfD1K0Iykdhz4e4rb4yRZA5P2ouhEARMWWMz9rxMUok+sY7y4FKuV75C8t 0xbcdLUk2/EkgOxlDRwB9q8u6xQVYUzdRCjrlrEYJnWvIf4sPd888A9bqnH++YKjN+jF dmZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=dD+rwXY/nYOWBAq4CYmtKPehya96hW8MC3evJji/Yec=; b=IeVlyWKdPG9TOnkzmKNwXj3k7YvULD2bzYZioqO4cHbg/MYesT+pIHdpG6kdHlG6O8 adzETf1b03u9uVpRUaA7EqtF74IxfSOgkbOlus7fUlEl0nJ/l/4zelUEYJr/0jgt4Xg4 Q+6BqG8EUcQLIlkubiqBMeuJWgtddaGVbNjF7dHldzcjKnnIqKvOXRuklGD2xs9Nz2Xt 9ST2iWoRTnsUsipK1z3LBi1kpWklCbQDMNgG/d0kkBOLmG+7VnDisfpPxLI/eSlRgR84 Z09cCeWvEIZ7VnpSLfsiUCLdJMj3BiK8zUMI7vWBzGDkaIahFrf6gwjR/4Hd6DsS1Ycm ngeg== X-Gm-Message-State: APjAAAUJf5A1NDFrd3WQYJT7D52Vrl1xdVngSZOeVQ8V3Pcj4Cfy7SFg e6EzlHxKNKhSPDBg+/wnI1I= X-Google-Smtp-Source: APXvYqyYVjjEk4t55bliwrB5kqrPSByuGmBtIo84DXhVvDur8OAwQWGVhoAdoOt78OMFi9yojAsMng== X-Received: by 2002:ac2:4a8f:: with SMTP id l15mr16241092lfp.21.1570435338163; Mon, 07 Oct 2019 01:02:18 -0700 (PDT) Received: from pc636 (h5ef52e31.seluork.dyn.perspektivbredband.net. [94.245.46.49]) by smtp.gmail.com with ESMTPSA id f21sm3218392lfm.90.2019.10.07.01.02.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Oct 2019 01:02:17 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 7 Oct 2019 10:02:09 +0200 To: Daniel Axtens Subject: Re: [PATCH v8 1/5] kasan: support backing vmalloc space with real shadow memory Message-ID: <20191007080209.GA22997@pc636> References: <20191001065834.8880-1-dja@axtens.net> <20191001065834.8880-2-dja@axtens.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191001065834.8880-2-dja@axtens.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, gor@linux.ibm.com, x86@kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, glider@google.com, luto@kernel.org, aryabinin@virtuozzo.com, linuxppc-dev@lists.ozlabs.org, dvyukov@google.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index a3c70e275f4e..9fb7a16f42ae 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -690,8 +690,19 @@ merge_or_add_vmap_area(struct vmap_area *va, > struct list_head *next; > struct rb_node **link; > struct rb_node *parent; > + unsigned long orig_start, orig_end; > bool merged = false; > > + /* > + * To manage KASAN vmalloc memory usage, we use this opportunity to > + * clean up the shadow memory allocated to back this allocation. > + * Because a vmalloc shadow page covers several pages, the start or end > + * of an allocation might not align with a shadow page. Use the merging > + * opportunities to try to extend the region we can release. > + */ > + orig_start = va->va_start; > + orig_end = va->va_end; > + > /* > * Find a place in the tree where VA potentially will be > * inserted, unless it is merged with its sibling/siblings. > @@ -741,6 +752,10 @@ merge_or_add_vmap_area(struct vmap_area *va, > if (sibling->va_end == va->va_start) { > sibling->va_end = va->va_end; > > + kasan_release_vmalloc(orig_start, orig_end, > + sibling->va_start, > + sibling->va_end); > + > /* Check and update the tree if needed. */ > augment_tree_propagate_from(sibling); > > @@ -754,6 +769,8 @@ merge_or_add_vmap_area(struct vmap_area *va, > } > > insert: > + kasan_release_vmalloc(orig_start, orig_end, va->va_start, va->va_end); > + > if (!merged) { > link_va(va, root, parent, link, head); > augment_tree_propagate_from(va); Hello, Daniel. Looking at it one more, i think above part of code is a bit wrong and should be separated from merge_or_add_vmap_area() logic. The reason is to keep it simple and do only what it is supposed to do: merging or adding. Also the kasan_release_vmalloc() gets called twice there and looks like a duplication. Apart of that, merge_or_add_vmap_area() can be called via recovery path when vmap/vmaps is/are not even setup. See percpu allocator. I guess your part could be moved directly to the __purge_vmap_area_lazy() where all vmaps are lazily freed. To do so, we also need to modify merge_or_add_vmap_area() to return merged area: diff --git a/mm/vmalloc.c b/mm/vmalloc.c index e92ff5f7dd8b..fecde4312d68 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -683,7 +683,7 @@ insert_vmap_area_augment(struct vmap_area *va, * free area is inserted. If VA has been merged, it is * freed. */ -static __always_inline void +static __always_inline struct vmap_area * merge_or_add_vmap_area(struct vmap_area *va, struct rb_root *root, struct list_head *head) { @@ -750,7 +750,10 @@ merge_or_add_vmap_area(struct vmap_area *va, /* Free vmap_area object. */ kmem_cache_free(vmap_area_cachep, va); - return; + + /* Point to the new merged area. */ + va = sibling; + merged = true; } } @@ -759,6 +762,8 @@ merge_or_add_vmap_area(struct vmap_area *va, link_va(va, root, parent, link, head); augment_tree_propagate_from(va); } + + return va; } static __always_inline bool @@ -1172,7 +1177,7 @@ static void __free_vmap_area(struct vmap_area *va) /* * Merge VA with its neighbors, otherwise just add it. */ - merge_or_add_vmap_area(va, + (void) merge_or_add_vmap_area(va, &free_vmap_area_root, &free_vmap_area_list); } @@ -1279,15 +1284,20 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) spin_lock(&vmap_area_lock); llist_for_each_entry_safe(va, n_va, valist, purge_list) { unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT; + unsigned long orig_start = va->va_start; + unsigned long orig_end = va->va_end; /* * Finally insert or merge lazily-freed area. It is * detached and there is no need to "unlink" it from * anything. */ - merge_or_add_vmap_area(va, + va = merge_or_add_vmap_area(va, &free_vmap_area_root, &free_vmap_area_list); + kasan_release_vmalloc(orig_start, + orig_end, va->va_start, va->va_end); + atomic_long_sub(nr, &vmap_lazy_nr); if (atomic_long_read(&vmap_lazy_nr) < resched_threshold) -- Vlad Rezki