Received: by 2002:ac0:aed5:0:0:0:0:0 with SMTP id t21csp2271321imb; Mon, 4 Mar 2019 00:20:09 -0800 (PST) X-Google-Smtp-Source: APXvYqynVOUJz34F19UQGcjWgn7T9fpZG/LX44FSW9Unlby6aIHl0SU8Xbuvg52zo6NnPX/0y2m3 X-Received: by 2002:a17:902:d702:: with SMTP id w2mr2589071ply.131.1551687608948; Mon, 04 Mar 2019 00:20:08 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1551687608; cv=none; d=google.com; s=arc-20160816; b=aBvVWhM8JW23rowfL3sVFTFa0UqGQgLlF1YGfK8bWxGAHvjy7ur0fCJncnnLgWj65B tcCjQiXWK/eS/qBVIUvZDZVL6VHG9uiYw1J1Qz6Hy0sUTlWI7NqNajwsXYEow1YczvF8 ryYOQq53nV1BYe+8BhgaDq5A4idHdTapjstd1+YcWquOtpCIRmKPNTeANenCCD6gTPwj MvG+E7sKDOM6g+Uycyb/jjf2PuMtgVdE0a8tlzfaKIGDMRG47mYcpMH/2v/Avl+sxFZv FsTfMrjMRnybPrci7gdyvue7TYwnjP2Yc4W6jyKdmsCn1HG4jy8nSlxKYEpUz7qexHqX Z1Kw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:dkim-signature; bh=WmNWNx1ySeryfAiTC7nsxWTTEIzxK5H5BDemAWXAwzo=; b=OZmvju9jkAJqoS3P/++HfEj3zJ3+R7Ur+B1LD3uzFcKIt/noE/LbrmV3fleQG19CgG CNCo5sp+iACGkk0oMip4qHpuH7t+sPrpB6y5VH4Jn4sWwsqy0AgF/tY+ijIH3Bsio8ka w3QGPma/AQEv/1eDvP5alQOBz3KL005BE5wV0gx/qCZ36K4acRGg/bxIcn6187wKghIs wcf/1OYovneFdXlFOCzKvM01mC6LBSl4pCb7SitpoOZekn9DeVsoZcVPW+IGvt7nKd3U XTkCX71RQtZ45xa6efXHUsDnUYVZcsonSii6wgqZFRHAo3abBOCKPw2+HYaD8sSkvsnJ /QEg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@shutemov-name.20150623.gappssmtp.com header.s=20150623 header.b="l/VKjl5b"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id d72si4845311pfm.284.2019.03.04.00.19.53; Mon, 04 Mar 2019 00:20:08 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@shutemov-name.20150623.gappssmtp.com header.s=20150623 header.b="l/VKjl5b"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726095AbfCDITX (ORCPT + 99 others); Mon, 4 Mar 2019 03:19:23 -0500 Received: from mail-lf1-f65.google.com ([209.85.167.65]:33228 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725974AbfCDITX (ORCPT ); Mon, 4 Mar 2019 03:19:23 -0500 Received: by mail-lf1-f65.google.com with SMTP id z23so2854083lfe.0 for ; Mon, 04 Mar 2019 00:19:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=WmNWNx1ySeryfAiTC7nsxWTTEIzxK5H5BDemAWXAwzo=; b=l/VKjl5b23njYyAzEe09qekKA+RlAwEsIYnGsfJn3nNoGpnfcYbol39NQJj7XC9/JU JtVDDmbrjadDfawxx2TfqKSTDXfHkwAW8LDG2JGzjoyofIjLTKWGsO7xS8VCqQeQf3iD O8WR/kKsYi9HbIr4qLrDxAiXTAAXNXeqw3avrUYKujwT6b1Xwh+pyup/nS6mpla6vKOa tXLqPekRpOmVAV60LJckMDfUyipTz9rR7rWzTDnLmFqxFyHq6dHhxeDpnoRLJsTB/4af 5Be7BlyE+BWCJlcStNCIAmvrR8WDSwFto/QisIW7qQ1WyqlVHodhMC2IegOqe8/VFvg2 7DUg== 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=WmNWNx1ySeryfAiTC7nsxWTTEIzxK5H5BDemAWXAwzo=; b=MbgIFXluMJBNN5/o0FJPLwrnU6ZRQH4gg4SMqPY6Dh2SXb+Nn2hj6i5z9K1eXPlnKl nvMcc6Fy357wkQ7V/8Ek/yxHWxliCalh73A+wD7ZSsAggp0nPS7oKu14w5Oh7PPeXUtp u8R3BWhWEiN5vY+bB/GOIC9c115ZfSaMJGc3JQQ7v0sdl9hLfXeToWh35VP5LJZWXE95 jyHcEWCKH7FzwzHsa+YNQoAMEo2Ol6HyX1KLThY5v/zzI0XCm/pDWEPATMIbImfWmdCe 5u6P+xYbcT/+DjoujvLfIEYBa18iDM1c8jXLrVuLw/mF/LE0/1zI/6MJk5Gq5NELRuIz hK/Q== X-Gm-Message-State: APjAAAXrNJsrOeX2WQC8fqlY5lx9q0+19TNpH+YYC8PtsZhwLs5tY3Ix yH8f186kNYhhrs3FlKc3k+zqhbLqJZtEfQ== X-Received: by 2002:a19:ca46:: with SMTP id h6mr8042457lfj.142.1551687561118; Mon, 04 Mar 2019 00:19:21 -0800 (PST) Received: from kshutemo-mobl1.localdomain (mm-159-97-122-178.mgts.dynamic.pppoe.byfly.by. [178.122.97.159]) by smtp.gmail.com with ESMTPSA id d26sm1389830ljc.15.2019.03.04.00.19.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Mar 2019 00:19:20 -0800 (PST) Received: by kshutemo-mobl1.localdomain (Postfix, from userid 1000) id 441613007CD; Mon, 4 Mar 2019 11:19:19 +0300 (+03) Date: Mon, 4 Mar 2019 11:19:19 +0300 From: "Kirill A. Shutemov" To: Jan Stancek Cc: linux-mm@kvack.org, akpm@linux-foundation.org, willy@infradead.org, peterz@infradead.org, riel@surriel.com, mhocko@suse.com, ying.huang@intel.com, jrdr.linux@gmail.com, jglisse@redhat.com, aneesh.kumar@linux.ibm.com, david@redhat.com, aarcange@redhat.com, raquini@redhat.com, rientjes@google.com, mgorman@techsingularity.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] mm/memory.c: do_fault: avoid usage of stale vm_area_struct Message-ID: <20190304081918.rrhyhyze237bpkqf@kshutemo-mobl1> References: <20190302185144.GD31083@redhat.com> <5b3fdf19e2a5be460a384b936f5b56e13733f1b8.1551595137.git.jstancek@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5b3fdf19e2a5be460a384b936f5b56e13733f1b8.1551595137.git.jstancek@redhat.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 03, 2019 at 08:28:04AM +0100, Jan Stancek wrote: > LTP testcase mtest06 [1] can trigger a crash on s390x running 5.0.0-rc8. > This is a stress test, where one thread mmaps/writes/munmaps memory area > and other thread is trying to read from it: > > CPU: 0 PID: 2611 Comm: mmap1 Not tainted 5.0.0-rc8+ #51 > Hardware name: IBM 2964 N63 400 (z/VM 6.4.0) > Krnl PSW : 0404e00180000000 00000000001ac8d8 (__lock_acquire+0x7/0x7a8) > Call Trace: > ([<0000000000000000>] (null)) > [<00000000001adae4>] lock_acquire+0xec/0x258 > [<000000000080d1ac>] _raw_spin_lock_bh+0x5c/0x98 > [<000000000012a780>] page_table_free+0x48/0x1a8 > [<00000000002f6e54>] do_fault+0xdc/0x670 > [<00000000002fadae>] __handle_mm_fault+0x416/0x5f0 > [<00000000002fb138>] handle_mm_fault+0x1b0/0x320 > [<00000000001248cc>] do_dat_exception+0x19c/0x2c8 > [<000000000080e5ee>] pgm_check_handler+0x19e/0x200 > > page_table_free() is called with NULL mm parameter, but because > "0" is a valid address on s390 (see S390_lowcore), it keeps > going until it eventually crashes in lockdep's lock_acquire. > This crash is reproducible at least since 4.14. > > Problem is that "vmf->vma" used in do_fault() can become stale. > Because mmap_sem may be released, other threads can come in, > call munmap() and cause "vma" be returned to kmem cache, and > get zeroed/re-initialized and re-used: > > handle_mm_fault | > __handle_mm_fault | > do_fault | > vma = vmf->vma | > do_read_fault | > __do_fault | > vma->vm_ops->fault(vmf); | > mmap_sem is released | > | > | do_munmap() > | remove_vma_list() > | remove_vma() > | vm_area_free() > | # vma is released > | ... > | # same vma is allocated > | # from kmem cache > | do_mmap() > | vm_area_alloc() > | memset(vma, 0, ...) > | > pte_free(vma->vm_mm, ...); | > page_table_free | > spin_lock_bh(&mm->context.lock);| > | > > Cache mm_struct to avoid using potentially stale "vma". > > [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/mtest06/mmap1.c > > Signed-off-by: Jan Stancek > Reviewed-by: Andrea Arcangeli Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov