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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05BA9C52D7C for ; Mon, 19 Aug 2024 05:56:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7A6316B0083; Mon, 19 Aug 2024 01:56:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 756E66B0085; Mon, 19 Aug 2024 01:56:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5F7B16B0088; Mon, 19 Aug 2024 01:56:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 3CD966B0083 for ; Mon, 19 Aug 2024 01:56:24 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id AC1C9A0FEF for ; Mon, 19 Aug 2024 05:56:23 +0000 (UTC) X-FDA: 82467935046.23.4AD9CBD Received: from AUS01-SY4-obe.outbound.protection.outlook.com (mail-sy4aus01olkn2093.outbound.protection.outlook.com [40.92.62.93]) by imf16.hostedemail.com (Postfix) with ESMTP id A2B50180003 for ; Mon, 19 Aug 2024 05:56:20 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=outlook.com header.s=selector1 header.b=VBJCKBAg; dmarc=pass (policy=none) header.from=outlook.com; spf=pass (imf16.hostedemail.com: domain of rsworktech@outlook.com designates 40.92.62.93 as permitted sender) smtp.mailfrom=rsworktech@outlook.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724046894; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=9PtexpzEd/3bcFRDLT5Hm8ZbeEY2R42umcTdiP4gRVI=; b=fOmRSv+hpKllO09yD/KlrvSdFa2srSUh58P+dL8sbdNbgYNCaafTTaGJvu1YCmqbf4WV/n uttfpcQlrXGFp2Z8XbX9sIDiSp6u6kKXLvT5SvpRhmrMOBCIi6nPyZ6npYNtbjmpqgQ0fq JZXoxKWYgPM4qPJCFnaAAvSkf29nP3c= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1724046894; a=rsa-sha256; cv=pass; b=6kQQHi0A5yT+Ou5zWl8tBvOJuliJLLfaRs01WmQjaflK5ZlxDSjYMyamYhzNxsnkkutxqM ByXr3+SBT+9ybqxHr+C2AVewj5e7QEceMcIB86QgkqVfKiyWmgM7eLhR79pmeaEVk2LjIf i6IexubgbQi83Mb5nUcEpiPF7/wM5xs= ARC-Authentication-Results: i=2; imf16.hostedemail.com; dkim=pass header.d=outlook.com header.s=selector1 header.b=VBJCKBAg; dmarc=pass (policy=none) header.from=outlook.com; spf=pass (imf16.hostedemail.com: domain of rsworktech@outlook.com designates 40.92.62.93 as permitted sender) smtp.mailfrom=rsworktech@outlook.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ZEiMRqT7MLTbj078A55940sRny8kxDBsh6/vUWpImDGVqFwaEOxvWFqOMwm8kjcKLxPgiw/SMZICPkR2zHL3Wn417QANuKRk1CrH1M5b35rruB0WkFMUgvq56T6rwGGYj6t8j1OqQ/nPQcc0OxrI6HXjn2xDISzmfYoEWUrtjAGxC8O2aRONj+PTY4LNTcfHwU/ybgkXHChFKJLcqqL89Vu7+cDkxo6VGWFLhJPbs6j/6Y9OvJlMTLH5aW2jb2ObE/g/GrayUs4DmkPpF1bl8fP+UzKJlHgEgG6UehyjqOYA52QU3x5rAyy4sSzeKqvfx9zyHWufnWRFDKX1aFQXPA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=9PtexpzEd/3bcFRDLT5Hm8ZbeEY2R42umcTdiP4gRVI=; b=ipCamXvkr9G9SQVUfI2B27l8LOOOP9/FbZdxBmbmslaT034QevEGzCepaF+9rJQpAZ9LolZMHf5Z71f08EA+VZNTomvQgPZITCRX4e7RkjIlrGFyNMVLCRSnyXhq5zyyYI3sKuiT7GJrR1rmN4Dt03WOJWw6JxFxB1pprjFpOHrzPeRZBUXD4f51PIBMrg99+DlzruiDqwn2UIDUCyVOwj1gBO0BzPDer0q4/vydQjHleX7TNtsCwa+vVrSHnAC1jQvOR+axPDJxhAgtk7BNC7YHCU+yvuIM++xMgLCs+jqHyHCst/ir8TBOfp0XvSOUD03LXruQBzwy7cm1rLWu4w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=outlook.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=9PtexpzEd/3bcFRDLT5Hm8ZbeEY2R42umcTdiP4gRVI=; b=VBJCKBAgBGfLEfxWexLoQnUdCdJEvVTlbWoyGCEw9NBLyyML4tluuDUWOIoCcx0owYwcMbpKcoCYbzxrGi3lII9rRgUzGC2b1imTsnkaEnySm40f3HTji6Rl5JjKJxZ+8/TugH6pZsvT0Ngkzb3RPQIofsYcAaXpT+8S3qmb0x7W9M83P7Id2gmvrMdtbaZ1PvqbkWU1jH5NxfGscSXBVtm5SFyzNiSrvSZkR3aV56V7/tHm7/U407+rZ/aYZAWWJ+6GrewKHcPXVEcTSw9H5NV2hwIVtp10rKZPIHcQlBR0V5qBGCx0YVjb1JL6jTu/9jOFXqmbMyLcYoJDMJ5X0A== Received: from MEYP282MB2312.AUSP282.PROD.OUTLOOK.COM (2603:10c6:220:ff::9) by ME0P282MB4328.AUSP282.PROD.OUTLOOK.COM (2603:10c6:220:227::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7875.21; Mon, 19 Aug 2024 05:56:13 +0000 Received: from MEYP282MB2312.AUSP282.PROD.OUTLOOK.COM ([fe80::6174:52de:9210:9165]) by MEYP282MB2312.AUSP282.PROD.OUTLOOK.COM ([fe80::6174:52de:9210:9165%4]) with mapi id 15.20.7875.019; Mon, 19 Aug 2024 05:56:13 +0000 Message-ID: Date: Mon, 19 Aug 2024 13:55:57 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] riscv: mm: Use hint address in mmap if available To: Palmer Dabbelt , Charlie Jenkins Cc: cyy@cyyself.name, alexghiti@rivosinc.com, Paul Walmsley , aou@eecs.berkeley.edu, shuah@kernel.org, corbet@lwn.net, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org References: Content-Language: en-US From: Levi Zim In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TMN: [WNCVloEgJucfNPQxOPeQ0VhQ7jSUWkrTAwD+5WvngAIc2m6zSc0X3bIIWdBrmC+j] X-ClientProxiedBy: TY2PR02CA0055.apcprd02.prod.outlook.com (2603:1096:404:e2::19) To MEYP282MB2312.AUSP282.PROD.OUTLOOK.COM (2603:10c6:220:ff::9) X-Microsoft-Original-Message-ID: MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MEYP282MB2312:EE_|ME0P282MB4328:EE_ X-MS-Office365-Filtering-Correlation-Id: bdcd4fbe-fb54-49d3-4e42-08dcc013a1a8 X-Microsoft-Antispam: BCL:0;ARA:14566002|8060799006|19110799003|15080799003|461199028|5072599009|4302099013|3412199025|440099028|1602099012; X-Microsoft-Antispam-Message-Info: 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 X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UTVCZG12M2tRV2VvMEtWM3UzODlBTDVZZk1xWDlRZnd4djBRaEZ1UGtIOXJ4?= =?utf-8?B?c0h5WCtZTzJKazZySDNYdVdNeGJzVG9mNklpM21vczVPTnVyYVVEUDFRU1Bi?= =?utf-8?B?M2szQ3ltb2EyeUNxZW1VdWJkR2Q2RWtzemxndEc1OXlidGpJa1FieWczVFhx?= =?utf-8?B?aFNuLzg2TGhmRkdwUWZpazU5NlBDTVVNUnpCRWxCWU9FcDBpU2VOdllkR2VJ?= =?utf-8?B?VVgzUXo2ZEI0dGwrMHlKNWRmbnpFS3g4cGhzd0tzdTlpU2kwdXVJOStPMkth?= =?utf-8?B?UEtlNUNiZzBkWnkvdGVXaEI1V0oyS2JrZFRQTzI4WlZyR1JkOWZnWmlZUSs5?= =?utf-8?B?b0RQZ1Zkblo5a1B6Tmk0SjBhcnpCWVRjV1FIUUIrWUh4bCtsU3RhVjRTZmNm?= =?utf-8?B?UkF3Yk9Od3NPL1lwS3R5dHZOSi9mdnVHVVUyeERnZUdaczNxMnRaUkIya2RP?= =?utf-8?B?THN3VXFrWXBETHJ0TldwRjRwYmRmSUdwOWt3WXlmV21wY3czd1lhVE5DYVlL?= =?utf-8?B?ZG1ka0hYMmtiUTZxMlMxaEY5U1A5VFZjOVBRYzErMnJDRzV3VTJRdlJWVjdC?= =?utf-8?B?bHVxZ2s0WU5ZOWFDL1FxVVcvenFMdHcxbEtxckJrdFAvSHFveTVMelREbDNq?= =?utf-8?B?Nm0xekxQdVo1c0dTV0x3MEJsNXNJNytDcFpxa1pPQk9ZUEc5QVVXbWJqYURH?= =?utf-8?B?eW1XdjNGWTEzYVIrZ2E3Z1Vib2orMStkMkVSQUJMQmp6RWlrVjRSRzljd0kx?= =?utf-8?B?QmlPWG9TUlZnSGFJNlZiR1BYR1ZHVEMvVk8yV3Y5NHNDUTNMMjBsVVR3dW9y?= =?utf-8?B?aVp2YjJNZEZlVG5UemFwNFhIeXk5VG13QWl1cGE4L29GeFEyUEV1OEpFdnRU?= =?utf-8?B?aUZ0cC9pY095alY1K1kxVHRSeldKaFdpNnRWeUJSdnArQnZUVWgwekQrbC80?= =?utf-8?B?bkN3TVBTdHpjV0lsL2laTVREM0dGZXZab2JpNThKelI5MENOU2tsRTYwY0NC?= =?utf-8?B?UTYxcCsrTDUrcjNPbTdvdGJLMmY4MEhCSFRyRkJYNlRuY1pXUHVSeVRuUVpP?= =?utf-8?B?ak1zOGdEd2NxK3JsMTRRTEZXNy9HQTBTOEZadnRTNGI0RFFtbDZaOTI1VEps?= =?utf-8?B?S09QUkJuN0ppMldwUHBTU0FYL1Z1bjRpcVQ0b01tSXZ6R1lSRzVHUk4wdzY3?= =?utf-8?B?YzhQbzJuZlR5VXJrOEllOWQvSHRTeU5CeWgwdlFTNjQ4MmNMR1VLY041NUNS?= =?utf-8?B?c1ZEYTZpSnkxY3VZengxL0MxM3AxYTd1dW82ZGF3OTlJQnQ2SXdiTnRwRHhv?= =?utf-8?B?RVhSWHRVblc0bVBITWZ6MjFieVJac2ZRRVhIaTVhc01hU2w5bTVpTWVpallj?= =?utf-8?B?c2JPYjl1cWxRV3JXYjJ3VjZwRkdsc3IxeG1IRVU2YlF3YTBkUTllT3BqSkdH?= =?utf-8?B?ZUhhK2wvM2VlZDhsRDY0WnJpRUtlU05MMGFrUDQ5U1EzUnZ3VVdoSXBZTGRW?= =?utf-8?B?amo1Tk02NlZGRlh5aW54bXhRS0s1Tk0vMFhsQ0pCUy8yVGpGOGQrVnd3R0pD?= =?utf-8?B?SzhMR2NhTGV2Vlp3cWZEL0cydU5jWVhFMjJrVXdIWWVuNVpEeW9QQWFXalFN?= =?utf-8?B?alVYWVJyZWg3M0FIMDdLbEZOY1JIY2szZFEzUG5sMGhZaUszQzZ2SVZyaC9H?= =?utf-8?B?MWx3cVFveWxmZXJtZDBuU1A1TGVLYWs4RFU1WVB3dUhmRjBacVJ0b1RVRnNI?= =?utf-8?Q?nh3uC/DzBZrirSu0jVY2wWAWbZgwms6hBJrJV/t?= X-OriginatorOrg: outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: bdcd4fbe-fb54-49d3-4e42-08dcc013a1a8 X-MS-Exchange-CrossTenant-AuthSource: MEYP282MB2312.AUSP282.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Aug 2024 05:56:13.1367 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-Transport-CrossTenantHeadersStamped: ME0P282MB4328 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: A2B50180003 X-Stat-Signature: f13faawh61eruztkuyi73uyz78zmgzsq X-Rspam-User: X-HE-Tag: 1724046980-536735 X-HE-Meta: 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 HGCo0bXe 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 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: List-Subscribe: List-Unsubscribe: On 2024-03-22 22:06, Palmer Dabbelt wrote: > On Thu, 01 Feb 2024 18:28:06 PST (-0800), Charlie Jenkins wrote: >> On Wed, Jan 31, 2024 at 11:59:43PM +0800, Yangyu Chen wrote: >>> On Wed, 2024-01-31 at 22:41 +0800, Yangyu Chen wrote: >>> > On Tue, 2024-01-30 at 17:07 -0800, Charlie Jenkins wrote: >>> > > On riscv it is guaranteed that the address returned by mmap is less >>> > > than >>> > > the hint address. Allow mmap to return an address all the way up to >>> > > addr, if provided, rather than just up to the lower address space. >>> > > > > This provides a performance benefit as well, allowing mmap >>> to exit >>> > > after >>> > > checking that the address is in range rather than searching for a >>> > > valid >>> > > address. >>> > > > > It is possible to provide an address that uses at most the same >>> > > number >>> > > of bits, however it is significantly more computationally expensive >>> > > to >>> > > provide that number rather than setting the max to be the hint >>> > > address. >>> > > There is the instruction clz/clzw in Zbb that returns the highest >>> > > set >>> > > bit >>> > > which could be used to performantly implement this, but it would >>> > > still >>> > > be slower than the current implementation. At worst case, half of >>> > > the >>> > > address would not be able to be allocated when a hint address is >>> > > provided. >>> > > > > Signed-off-by: Charlie Jenkins >>> > > --- >>> > >  arch/riscv/include/asm/processor.h | 27 +++++++++++--------------- >>> > > - >>> > >  1 file changed, 11 insertions(+), 16 deletions(-) >>> > > > > diff --git a/arch/riscv/include/asm/processor.h >>> > > b/arch/riscv/include/asm/processor.h >>> > > index f19f861cda54..8ece7a8f0e18 100644 >>> > > --- a/arch/riscv/include/asm/processor.h >>> > > +++ b/arch/riscv/include/asm/processor.h >>> > > @@ -14,22 +14,16 @@ >>> > > >>> > >  #include >>> > > >>> > > -#ifdef CONFIG_64BIT >>> > > -#define DEFAULT_MAP_WINDOW    (UL(1) << (MMAP_VA_BITS - 1)) >>> > > -#define STACK_TOP_MAX        TASK_SIZE_64 >>> > > - >>> > >  #define arch_get_mmap_end(addr, len, flags)            \ >>> > >  ({                                \ >>> > >      unsigned long >>> > > mmap_end;                    \ >>> > >      typeof(addr) _addr = (addr);                \ >>> > > -    if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && >>> > > is_compat_task())) \ >>> > > +    if ((_addr) == 0 ||                    \ >>> > > +        (IS_ENABLED(CONFIG_COMPAT) && is_compat_task()) ||    \ >>> > > +        ((_addr + len) > BIT(VA_BITS - >>> > > 1)))            \ >>> > >          mmap_end = STACK_TOP_MAX;            \ >>> > > -    else if ((_addr) >= VA_USER_SV57) \ >>> > > -        mmap_end = STACK_TOP_MAX;            \ >>> > > -    else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= >>> > > VA_BITS_SV48)) \ >>> > > -        mmap_end = VA_USER_SV48;            \ >>> > >      else                            \ >>> > > -        mmap_end = VA_USER_SV39;            \ >>> > > +        mmap_end = (_addr + len);            \ >>> > >      mmap_end;                        \ >>> > >  }) >>> > > >>> > > @@ -39,17 +33,18 @@ >>> > >      typeof(addr) _addr = (addr);                \ >>> > >      typeof(base) _base = (base);                \ >>> > >      unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base);    \ >>> > > -    if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && >>> > > is_compat_task())) \ >>> > > +    if ((_addr) == 0 ||                    \ >>> > > +        (IS_ENABLED(CONFIG_COMPAT) && is_compat_task()) ||    \ >>> > > +        ((_addr + len) > BIT(VA_BITS - >>> > > 1)))            \ >>> > >          mmap_base = (_base);                \ >>> > > -    else if (((_addr) >= VA_USER_SV57) && (VA_BITS >= >>> > > VA_BITS_SV57)) \ >>> > > -        mmap_base = VA_USER_SV57 - rnd_gap; \ >>> > > -    else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= >>> > > VA_BITS_SV48)) \ >>> > > -        mmap_base = VA_USER_SV48 - rnd_gap; \ >>> > >      else                            \ >>> > > -        mmap_base = VA_USER_SV39 - rnd_gap; \ >>> > > +        mmap_base = (_addr + len) - rnd_gap; \ >>> > >      mmap_base;                        \ >>> > >  }) >>> > > >>> > > +#ifdef CONFIG_64BIT >>> > > +#define DEFAULT_MAP_WINDOW    (UL(1) << (MMAP_VA_BITS - 1)) >>> > > +#define STACK_TOP_MAX        TASK_SIZE_64 >>> > >  #else >>> > >  #define DEFAULT_MAP_WINDOW    TASK_SIZE >>> > >  #define STACK_TOP_MAX        TASK_SIZE >>> > > > > I have carefully tested your patch on qemu with sv57. A bug >>> that >>> > needs >>> > to be solved is that mmap with the same hint address without >>> > MAP_FIXED >>> > set will fail the second time. >>> > > Userspace code to reproduce the bug: >>> > > #include >>> > #include >>> > #include >>> > > void test(char *addr) { >>> >     char *res = mmap(addr, 4096, PROT_READ | PROT_WRITE, >>> > MAP_ANONYMOUS >>> > > MAP_PRIVATE, -1, 0); >>> >     printf("hint %p got %p.\n", addr, res); >>> > } >>> > > int main (void) { >>> >     test(1<<30); >>> >     test(1<<30); >>> >     test(1<<30); >>> >     return 0; >>> > } >>> > > output: >>> > > hint 0x40000000 got 0x40000000. >>> > hint 0x40000000 got 0xffffffffffffffff. >>> > hint 0x40000000 got 0xffffffffffffffff. >>> > > output on x86: >>> > > hint 0x40000000 got 0x40000000. >>> > hint 0x40000000 got 0x7f9171363000. >>> > hint 0x40000000 got 0x7f9171362000. >>> > > It may need to implement a special arch_get_unmapped_area and >>> > arch_get_unmapped_area_topdown function. >>> > >>> This is because hint address < rnd_gap. I have tried to let mmap_base = >>> min((_addr + len), (base) + TASK_SIZE - DEFAULT_MAP_WINDOW). However it >>> does not work for bottom-up while ulimit -s is unlimited. You said this >>> behavior is expected from patch v2 review. However it brings a new >>> regression even on sv39 systems. >>> >>> I still don't know the reason why use addr+len as the upper-bound. I >>> think solution like x86/arm64/powerpc provide two address space switch >>> based on whether hint address above the default map window is enough. >>> >> >> Yep this is expected. It is up to the maintainers to decide. > > Sorry I forgot to reply to this, I had a buffer sitting around > somewhere but I must have lost it. > > I think Charlie's approach is the right way to go.  Putting my > userspace hat on, I'd much rather have my allocations fail rather than > silently ignore the hint when there's memory pressure. > > If there's some real use case that needs these low hints to be > silently ignored under VA pressure then we can try and figure > something out that makes those applications work. I could confirm that this patch has broken chromium's partition allocator on riscv64. The minimal reproduction I use is chromium-mmap.c: #include #include int main() {     void* expected = (void*)0x400000000;     void* addr = mmap(expected, 17179869184, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);     if (addr != expected) {         printf("Not expected address: %p != %p\n", addr, expected);     }     expected = (void*)0x3fffff000;     addr = mmap(expected, 17179873280, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);     if (addr != expected) {         printf("Not expected address: %p != %p\n", addr, expected);     }     return 0; } The second mmap fails with ENOMEM. Manually reverting this commit fixes the issue for me. So I think it's clearly a regression and breaks userspace. See also https://github.com/riscv-forks/electron/issues/4 >> >> - Charlie Sincerely, Levi