From owner-freebsd-ppc@freebsd.org Thu Jan 9 11:12:37 2020 Return-Path: Delivered-To: freebsd-ppc@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 1221B1E9FE4 for ; Thu, 9 Jan 2020 11:12:37 +0000 (UTC) (envelope-from leandro.lupori@gmail.com) Received: from mail-il1-x12e.google.com (mail-il1-x12e.google.com [IPv6:2607:f8b0:4864:20::12e]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47tk3m1KKPz3yf7; Thu, 9 Jan 2020 11:12:36 +0000 (UTC) (envelope-from leandro.lupori@gmail.com) Received: by mail-il1-x12e.google.com with SMTP id t8so5405315iln.4; Thu, 09 Jan 2020 03:12:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=hQ9zH7iKy8dEvKdepgTkg6ici0lXdr7by1zMD2MEa7o=; b=aeMv08hOYlOTuDdJiGRX21WaHwFpAKRPJ0G4DmWpEfRqDne5xX0D92wXWa90kaUnEH LDUwlY2QVOXdRmII4SnphjmEtHg1ymgLdHZmeB5hlcBbQ5c4Mv22/JG1ui+ui4mRffe1 XM1vdO/1TFzSyJo/YN9rNoVdfrl0itLwveqacxodk/xVF2uiSeyEg9j1p/zo+2k+c2/B u72z+vLXFFqXIcbwbMRq7wBoHu4FvTSapYGor/aC0YAQrKfgqi/zrTPJcOLC3kQ6Iu62 FSRpXCHcnxU4LhJkg73PhwHL2W8BMVdcbHG6QPEpTAF3BeKTzXmXFNkQseIt+n84jfFT CG8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=hQ9zH7iKy8dEvKdepgTkg6ici0lXdr7by1zMD2MEa7o=; b=eq9FQ6VegZC7HL50aqXjQ5H7HaATzJtF0x7Zs946gr/91JCU/d15j8EG/GfXvbdCFn xrqkQfD90gmX+yzlk22U3dppJp+goyNNrVwwkXRgqIhWDQdBLZjWbg7Yej42sq/zJp7i zsEApU5Fwsz/026C7O04DUoqRG8ry+dXRS/b5YpeY/DNuD23n8NGArXvQnIpJC9Bbdg/ FeL694tQ/0tEGkLvwW7YLPxTm8eU7Hr5sQbUvm1S+BRFiebXXuf8B5plE0ElV+Ll42TU rDMf5LY7gkVSFbYkb7vrablVVnXQETWH/Mq3RJm5v3SD9cTA/n7sZ1yEqjOXFn+LvN+5 eUaA== X-Gm-Message-State: APjAAAXHpGGneEEB90tZYIgZ+O3jqVtFUJGUQfMxZqhaqRaknGkJGJ+3 N+bJBEMF/Q0VHp7ghtOQHjMroyuGXFs6FFWtoDCBAKaE X-Google-Smtp-Source: APXvYqz93AKDG0IA5VbR1VIqkyYNLt+6krrvlRBbp9eQhDAuDOe3dmLPKRzFKxc+VngxTykb6/i8GVDPp9NhryP8Yq0= X-Received: by 2002:a92:5b49:: with SMTP id p70mr8003345ilb.209.1578568354710; Thu, 09 Jan 2020 03:12:34 -0800 (PST) MIME-Version: 1.0 References: <022334D3-B60E-440F-A514-8D8002B65CB4.ref@yahoo.com> <022334D3-B60E-440F-A514-8D8002B65CB4@yahoo.com> In-Reply-To: <022334D3-B60E-440F-A514-8D8002B65CB4@yahoo.com> From: Leandro Lupori Date: Thu, 9 Jan 2020 08:12:23 -0300 Message-ID: Subject: Re: A possible unbounded loop in moea_sync_icache: why sys/vm/mlock_test:mlock__copy_on_write_vnode fails? To: Mark Millard Cc: Justin Hibbits , FreeBSD PowerPC ML , "bdragon@freebsd.org" X-Rspamd-Queue-Id: 47tk3m1KKPz3yf7 X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=aeMv08hO; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of leandrolupori@gmail.com designates 2607:f8b0:4864:20::12e as permitted sender) smtp.mailfrom=leandrolupori@gmail.com X-Spamd-Result: default: False [-2.00 / 15.00]; TO_DN_EQ_ADDR_SOME(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36]; FREEMAIL_FROM(0.00)[gmail.com]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; FREEMAIL_TO(0.00)[yahoo.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; SUBJECT_ENDS_QUESTION(1.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; IP_SCORE(0.00)[ip: (-8.90), ipnet: 2607:f8b0::/32(-2.12), asn: 15169(-1.85), country: US(-0.05)]; TAGGED_FROM(0.00)[]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; DWL_DNSWL_NONE(0.00)[gmail.com.dwl.dnswl.org : 127.0.5.0]; IP_SCORE_FREEMAIL(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[e.2.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; FREEMAIL_CC(0.00)[gmail.com]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Jan 2020 11:12:37 -0000 Interesting, this looks like the same issue that was fixed on 64-bit some time ago: https://reviews.freebsd.org/D19149. On Thu, Jan 9, 2020 at 3:03 AM Mark Millard via freebsd-ppc < freebsd-ppc@freebsd.org> wrote: > In the statement: > > lim = round_page(va); > > later below in moea_sync_icache, it uses: > > #define round_page(x) (((x) + PAGE_MASK) & ~PAGE_MASK) > > So, for PAGE_MASK==(4096u-1u) the statement translates > to, in essence (the u's are conceptual here): > > lim = ((va)+4095u) & ~4095u; > > That means that if va%4096u==0 then teh result > is lim==va . > > In turn, that means that: > > len = MIN(lim - va, sz); > > results in len==0. > > That in turn means that: > > sz -= len; > > does not change sz. > > Overall result: the loop tesing sz>0 does not > terminate. > > I expect that is why the kyua test: > > sys/vm/mlock_test:mlock__copy_on_write_vnode : > > is failing. > > > The code in question: > > static void > moea_sync_icache(mmu_t mmu, pmap_t pm, vm_offset_t va, vm_size_t sz) > { > struct pvo_entry *pvo; > vm_offset_t lim; > vm_paddr_t pa; > vm_size_t len; > > PMAP_LOCK(pm); > while (sz > 0) { > lim = round_page(va); > len = MIN(lim - va, sz); > pvo = moea_pvo_find_va(pm, va & ~ADDR_POFF, NULL); > if (pvo != NULL) { > pa = (pvo->pvo_pte.pte.pte_lo & PTE_RPGN) | > (va & ADDR_POFF); > moea_syncicache(pa, len); > } > va += len; > sz -= len; > } > PMAP_UNLOCK(pm); > } > > > === > Mark Millard > marklmi at yahoo.com > ( dsl-only.net went > away in early 2018-Mar) > > _______________________________________________ > freebsd-ppc@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-ppc > To unsubscribe, send any mail to "freebsd-ppc-unsubscribe@freebsd.org" >