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=-19.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=ham 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 2B12FC433DB for ; Tue, 16 Mar 2021 17:31:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B288D64F17 for ; Tue, 16 Mar 2021 17:31:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B288D64F17 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4F26B6B006C; Tue, 16 Mar 2021 13:31:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4CA176B006E; Tue, 16 Mar 2021 13:31:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F8536B0070; Tue, 16 Mar 2021 13:31:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0179.hostedemail.com [216.40.44.179]) by kanga.kvack.org (Postfix) with ESMTP id 1361B6B006C for ; Tue, 16 Mar 2021 13:31:01 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id BEBCD180AD83A for ; Tue, 16 Mar 2021 17:31:00 +0000 (UTC) X-FDA: 77926427880.25.6AA3940 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) by imf24.hostedemail.com (Postfix) with ESMTP id E6650A0049EB for ; Tue, 16 Mar 2021 17:30:57 +0000 (UTC) Received: by mail-wm1-f52.google.com with SMTP id d191so10527756wmd.2 for ; Tue, 16 Mar 2021 10:30:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ure8kWkdZ5geLP/9Lu+/xSmpVEu0DA6buPVci38aSj0=; b=Z678/QuLnZrG4E0wQ6JR1/nIGj9Fs7Z8+aAZt8Mz8sYdje6igCKN2utV2igPfamrt3 ozvC+EoHpQ6EwT08H/KYiIED6ErrciMFxaQijeEGnrXKFlq2jVTYkwhxwFNNL73ZuXNE xNv7p0SDTg0Uv1pWfryHD6ci4FsT4tdONtkEhM1pE1cUFpsPmgdp1umhgu4KJG3vWW5t cWA4iUaDeT8XBmj08MWPoEi/wvTWp6syClumigtyAGVLiHq7G4kDn/y/CllVFlhSnXnP +vRXmM9mX1XZTlXN5/2u5jfOqHTpJ4Wmem107KL0SZARCwPvJACOoO4qe9HzSh/c2wBP 4vng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ure8kWkdZ5geLP/9Lu+/xSmpVEu0DA6buPVci38aSj0=; b=P95cm8UOYMnYH9irxurxYeMwuamn/l2ft/CdijDsvErWe5xAm6ypJ0LarWYe2nUqa1 O95N+jICR+apQAxI1yrJ4j+4r2nAWlDypjMkNUpuLtctxVxzFcwQpwiSv6vmgG/GCMcu 7f4EsbrFtJN+XHth8fHExaMdlj+1HJ+92wYEv57PTOJ0YTDIv/NhZElUxhAlULx+gC9Q zK523edXMUYbMym/IKi/8M37O+StTCQLpw0t3B6Ba0M5fUZfBrkXJFpSmaPptclLaTcV VLvsVOHuhIt0W4/s3nBWm4Hfvr06jpXD5JjB5bC/B/6fdFnyVCkl1z6bLJ7LpjBl2xLw fW8A== X-Gm-Message-State: AOAM533JiceTniSN8GHE6wKm1lw15VBh9V2++LZ8jDwfyTJxezyjHRie unxjvdq/zUPb28PzCtX/VJMDig== X-Google-Smtp-Source: ABdhPJytNagM4AIbMoENHxcjBnrn4JxwikwNeiZ2SKxSVH/A1ANipTJtB19WZ+2dS+sc8ya4+f0huw== X-Received: by 2002:a05:600c:1548:: with SMTP id f8mr135921wmg.81.1615915850632; Tue, 16 Mar 2021 10:30:50 -0700 (PDT) Received: from elver.google.com ([2a00:79e0:15:13:1d09:9676:5eaa:550]) by smtp.gmail.com with ESMTPSA id b65sm101820wmh.4.2021.03.16.10.30.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Mar 2021 10:30:49 -0700 (PDT) Date: Tue, 16 Mar 2021 18:30:00 +0100 From: Marco Elver To: Luis Henriques Cc: Alexander Potapenko , Dmitry Vyukov , Catalin Marinas , Andrew Morton , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: Issue with kfence and kmemleak Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.0.5 (2021-01-21) X-Stat-Signature: kc3xmup63hm9tf77ddq837og8rsesrb6 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E6650A0049EB Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf24; identity=mailfrom; envelope-from=""; helo=mail-wm1-f52.google.com; client-ip=209.85.128.52 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615915857-104045 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 16, 2021 at 04:42PM +0000, Luis Henriques wrote: > Hi! > > This is probably a known issue, but just in case: looks like it's not > possible to use kmemleak when kfence is enabled: Thanks for spotting this. > [ 0.272136] kmemleak: Cannot insert 0xffff888236e02f00 into the object search tree (overlaps existing) > [ 0.272136] CPU: 0 PID: 8 Comm: kthreadd Not tainted 5.12.0-rc3+ #92 > [ 0.272136] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014 > [ 0.272136] Call Trace: > [ 0.272136] dump_stack+0x6d/0x89 > [ 0.272136] create_object.isra.0.cold+0x40/0x62 > [ 0.272136] ? process_one_work+0x5a0/0x5a0 > [ 0.272136] ? process_one_work+0x5a0/0x5a0 > [ 0.272136] kmem_cache_alloc_trace+0x110/0x2f0 > [ 0.272136] ? process_one_work+0x5a0/0x5a0 > [ 0.272136] kthread+0x3f/0x150 > [ 0.272136] ? lockdep_hardirqs_on_prepare+0xd4/0x170 > [ 0.272136] ? __kthread_bind_mask+0x60/0x60 > [ 0.272136] ret_from_fork+0x22/0x30 > [ 0.272136] kmemleak: Kernel memory leak detector disabled > [ 0.272136] kmemleak: Object 0xffff888236e00000 (size 2097152): > [ 0.272136] kmemleak: comm "swapper", pid 0, jiffies 4294892296 > [ 0.272136] kmemleak: min_count = 0 > [ 0.272136] kmemleak: count = 0 > [ 0.272136] kmemleak: flags = 0x1 > [ 0.272136] kmemleak: checksum = 0 > [ 0.272136] kmemleak: backtrace: > [ 0.272136] memblock_alloc_internal+0x6d/0xb0 > [ 0.272136] memblock_alloc_try_nid+0x6c/0x8a > [ 0.272136] kfence_alloc_pool+0x26/0x3f > [ 0.272136] start_kernel+0x242/0x548 > [ 0.272136] secondary_startup_64_no_verify+0xb0/0xbb > > I've tried the hack below but it didn't really helped. Obviously I don't > really understand what's going on ;-) But I think the reason for this > patch not working as (I) expected is because kfence is initialised > *before* kmemleak. > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 3b8ec938470a..b4ffd7695268 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -631,6 +631,9 @@ void __init kfence_alloc_pool(void) > > if (!__kfence_pool) > pr_err("failed to allocate pool\n"); > + kmemleak_no_scan(__kfence_pool); > } Can you try the below patch? Thanks, -- Marco ------ >8 ------ diff --git a/mm/kfence/core.c b/mm/kfence/core.c index f7106f28443d..5891019721f6 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -481,6 +482,13 @@ static bool __init kfence_init_pool(void) addr += 2 * PAGE_SIZE; } + /* + * The pool is live and will never be deallocated from this point on; + * tell kmemleak this is now free memory, so that later allocations can + * correctly be tracked. + */ + kmemleak_free_part_phys(__pa(__kfence_pool), KFENCE_POOL_SIZE); + return true; err: