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=-6.6 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,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D0339C3A589 for ; Sun, 18 Aug 2019 07:47:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 788B720851 for ; Sun, 18 Aug 2019 07:47:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="A4os+5u3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 788B720851 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DCF536B0008; Sun, 18 Aug 2019 03:47:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D56F16B000A; Sun, 18 Aug 2019 03:47:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C1DCA6B000C; Sun, 18 Aug 2019 03:47:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0168.hostedemail.com [216.40.44.168]) by kanga.kvack.org (Postfix) with ESMTP id 9B2676B0008 for ; Sun, 18 Aug 2019 03:47:04 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 56AF38E5A for ; Sun, 18 Aug 2019 07:47:04 +0000 (UTC) X-FDA: 75834767568.19.seat56_3daccab1d8957 X-HE-Tag: seat56_3daccab1d8957 X-Filterd-Recvd-Size: 5631 Received: from mail-ed1-f68.google.com (mail-ed1-f68.google.com [209.85.208.68]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Sun, 18 Aug 2019 07:47:03 +0000 (UTC) Received: by mail-ed1-f68.google.com with SMTP id a21so8532631edt.11 for ; Sun, 18 Aug 2019 00:47:03 -0700 (PDT) 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=0i8dYHRhjyQq56TtntndePfnzxoMqtxxO44HUTYu3/I=; b=A4os+5u3AY9vy+3QQo6CEH4KDIVd4rEY00yVYB+1nr3SPCydBTHH0NOAOGDCZTwXoP dWGdwe5366Lr2S9fz2ZmeWNVYUC2YwIKV2bgX+BRfY+phiLBKAvPs/H/h45jDmL4CdGQ CteNzyH9QlemetYkgT9DeRfjDBH5U2LOUQIFhYjilIYw90x6pb1Rsu/2kRF9ZijBoo5B 8PWMwAOCDouoYs5TJHkVyJ0UqCQclg/bmcNadOReHzElgAnejEfXBij+QydXCVlKryu6 YTh8+9xgFIsSJTVT0rDxOec55sC5eyTtbR2z+YXabdtEdV4QEioEZNioH3vCjWqmfRKO dNPQ== 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=0i8dYHRhjyQq56TtntndePfnzxoMqtxxO44HUTYu3/I=; b=W0YaEIgs+LTPfBo3z3Cokult0tMmbWVY1FQQkbWeojuOt+kAT8wd1/55Af/Hdbxi6X KI0lkIsGNL1qmcF9TGIHcsn2YpxSf0O4oU2JAPQNo/aOlV6ATXCsWUz0+HW0oTeRETMd N3+hm/TbfCe1e8yaT/HQZVNAz8Y8niCc0lYW/A7LdXszzT1fJ/IiVsWSBHfBMm5FaOAt M3pscp6pK6AYZZP5w5K5TnZ3Jfoymm4QsU8vomvbIhjnmELuyb306Uq01dnQ/hJAIJwo 0bl7cC80LqA8Tgtceey12iOtRS7X0+KxinIO3pZl7hsjZIHE25Q7GuGi5yeOhETzLvsF UXow== X-Gm-Message-State: APjAAAVGJeb6AYm7tRMqDCEBnp+S1LOshtYAiaiISC4GJzx364M5P28B vjflR4wVo82rNvV7v69m8GXc8KjxH6O5cKV2rHrLUafb X-Google-Smtp-Source: APXvYqz1mUZECTJrsCX8TbM4B5MfF4HYsBDtV4p4ZNqdgilx7DGF6UwwN+cffa9ljLeQJ/iS6MkNUUMRvRqMIdwbhx4= X-Received: by 2002:aa7:d94f:: with SMTP id l15mr19034091eds.299.1566114422571; Sun, 18 Aug 2019 00:47:02 -0700 (PDT) MIME-Version: 1.0 References: <1566010813-27219-1-git-send-email-huangzhaoyang@gmail.com> <20190817183240.GM13294@shell.armlinux.org.uk> In-Reply-To: <20190817183240.GM13294@shell.armlinux.org.uk> From: Zhaoyang Huang Date: Sun, 18 Aug 2019 15:46:51 +0800 Message-ID: Subject: Re: [PATCH] arch : arm : add a criteria for pfn_valid To: Russell King - ARM Linux admin Cc: Andrew Morton , Zhaoyang Huang , Mike Rapoport , Rob Herring , Florian Fainelli , Geert Uytterhoeven , Doug Berger , "open list:MEMORY MANAGEMENT" , LKML Content-Type: text/plain; charset="UTF-8" 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 Sun, Aug 18, 2019 at 2:32 AM Russell King - ARM Linux admin wrote: > > On Sat, Aug 17, 2019 at 11:00:13AM +0800, Zhaoyang Huang wrote: > > From: Zhaoyang Huang > > > > pfn_valid can be wrong while the MSB of physical address be trimed as pfn > > larger than the max_pfn. > > What scenario are you addressing here? At a guess, you're addressing > the non-LPAE case with PFNs that correspond with >= 4GiB of memory? Please find bellowing for the callstack caused by this defect. The original reason is a invalid PFN passed from userspace which will introduce a invalid page within stable_page_flags and then kernel panic. [46886.723249] c7 [] (stable_page_flags) from [] (kpageflags_read+0x90/0x11c) [46886.723256] c7 r9:c101ce04 r8:c2d0bf70 r7:c2d0bf70 r6:1fbb10fb r5:a8686f08 r4:a8686f08 [46886.723264] c7 [] (kpageflags_read) from [] (proc_reg_read+0x80/0x94) [46886.723270] c7 r10:000000b4 r9:00000008 r8:c2d0bf70 r7:00000000 r6:00000001 r5:ed8e7240 [46886.723272] c7 r4:00000000 [46886.723280] c7 [] (proc_reg_read) from [] (__vfs_read+0x48/0x150) [46886.723284] c7 r7:c2d0bf70 r6:c0f09208 r5:c0a4f940 r4:c40326c0 [46886.723290] c7 [] (__vfs_read) from [] (vfs_read+0xa4/0x158) [46886.723296] c7 r9:a8686f08 r8:00000008 r7:c2d0bf70 r6:a8686f08 r5:c40326c0 r4:00000008 [46886.723301] c7 [] (vfs_read) from [] (SyS_pread64+0x80/0xb8) [46886.723306] c7 r8:00000008 r7:c0f09208 r6:c40326c0 r5:c40326c0 r4:fdd887d8 [46886.723315] c7 [] (SyS_pread64) from [] (ret_fast_syscall+0x0/0x28) > > > > > Signed-off-by: Zhaoyang Huang > > --- > > arch/arm/mm/init.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c > > index c2daabb..9c4d938 100644 > > --- a/arch/arm/mm/init.c > > +++ b/arch/arm/mm/init.c > > @@ -177,7 +177,8 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max_low, > > #ifdef CONFIG_HAVE_ARCH_PFN_VALID > > int pfn_valid(unsigned long pfn) > > { > > - return memblock_is_map_memory(__pfn_to_phys(pfn)); > > + return (pfn > max_pfn) ? > > + false : memblock_is_map_memory(__pfn_to_phys(pfn)); > > } > > EXPORT_SYMBOL(pfn_valid); > > #endif > > -- > > 1.9.1 > > > > > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up > According to speedtest.net: 11.9Mbps down 500kbps up