From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751521AbdJTAif (ORCPT ); Thu, 19 Oct 2017 20:38:35 -0400 Received: from mail-eopbgr40115.outbound.protection.outlook.com ([40.107.4.115]:52521 "EHLO EUR03-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751153AbdJTAie (ORCPT ); Thu, 19 Oct 2017 20:38:34 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=avagin@virtuozzo.com; Date: Thu, 19 Oct 2017 17:38:23 -0700 From: Andrei Vagin To: Josh Poimboeuf Cc: Ingo Molnar , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, hpa@zytor.com, tglx@linutronix.de Subject: Re: [2/2] x86/unwind: Make CONFIG_UNWINDER_ORC=y the default in kconfig for 64-bit Message-ID: <20171020003822.GA14054@outlook.office365.com> References: <9b1237bbe7244ed9cdf8db2dcb1253e37e1c341e.1507924831.git.jpoimboe@redhat.com> <20171019165103.GA15123@outlook.office365.com> <20171019181655.7yjgxuebkqzzcz4f@treble> <20171019223522.GA4499@outlook.office365.com> MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <20171019223522.GA4499@outlook.office365.com> User-Agent: Mutt/1.8.3 (2017-05-23) X-Originating-IP: [65.152.152.74] X-ClientProxiedBy: AM5PR06CA0018.eurprd06.prod.outlook.com (2603:10a6:206:2::31) To VI1PR08MB0749.eurprd08.prod.outlook.com (2a01:111:e400:5a04::11) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 36d06374-2fa2-4786-ca80-08d51752e37e X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(4534020)(4602075)(4627075)(201703031133081)(201702281549075)(2017052603199);SRVR:VI1PR08MB0749; X-Microsoft-Exchange-Diagnostics: 1;VI1PR08MB0749;3:HdurodNBJdZBTjz0SQ0RVg+5/B7jV7+ebJ2uqcH6t3gdO+R5yhYRKV08seN3Ca5vgib8JlushJ0vQIaHDdqWBS9tLJldbqigGvI88XwtpuGBpe8ZeTX/7XKv32C24ASYHP4pLwPl4hQnCfmp0XfA/keIt7G5UyrI5INxWqhJB75JqarCOV52i4j1j3NehcEpLS1p/wgGfOHy/2WabUmgUY+zXFO+dn/Slffj7U4HGnYF+nv3cf7eLT9GwwgcFmOx;25:n2eeWkeMp4Oim0ke2SfzgPcejSMLOqT+3esYjX2fOrdSJoPH81UWi12qw8AR/9eVXxPVsA35GRqYOONZy1EiYutdNgu2erjwnFnh5vwp/hM5kTiX+6Z7EqK4HdpeUwbKzwykB/daZdpNiKhhsk7lVS+yP5IDPgHx09sYuzCg6gwTcTTasZtWfzkyM3Y0IjL9P6FdTUd/1zEOzzv6TyLpUwme7M3udr8Gry3/FX+fvNxztKaxLP4cwUY+DnqHG3ba4FW8vv5yBN8WcHgpUmO6A2OPK3phSqn9JRQtPjSdONY3jbXQzt1RzLuezRjCDVCQeyzMSuDK7HdIBtLcDRIG3q/srg+271y+E7pfCsm+/zY=;31:zdENK2gCF2LzcXGEYJqfZ/9wBKnArVtzCm1Uf+BR1rqfV2W8F43PPqAfBgIXvHE2JloZwDwWL8hsc+MSp3C3y9b8AQ0rTzBs7LTAW84skXGNZXYMVO2Uji4VKK8TJAsh3TxxIxmPi67NAbA6oNurbdQLCgraTzU2yQk/YXU/KFBWK3a9iwjzAJWC+5/FLrPJQwF+/j/peGCWpeSI+pWyUVnGL4s2lU1PFOMIE+Cxphc= X-MS-TrafficTypeDiagnostic: VI1PR08MB0749: X-Microsoft-Exchange-Diagnostics: 1;VI1PR08MB0749;20:DiWMk/y8uqn+aa7gVlYFKKwo0XsnsMkfpSvRgcEreSGb8rW+RqzsN60LtobiOakF/Nww3oe6bA5ugImXw6HBTJmmdAuo7bQ77gW3uHkD4Mgxf5kYWKsm9FcP24Sat2hmtXD3GrSC/L9dfozvWzQmUjRBipiHJlAS7Y8BXI8ItgzZNBsAHW8yvUSVjdlOPnm9tGSzsVpctZprZKBp2jylD856jEm5VNGm19r2FTbaXpLUEl6NUopNdc/hGpu6b4L9xH/frUPGAoarw3yOQhGIA30EFB+Nukn87kdnfMC/9oVSuUEclM7GWf9JiVBlmDvghdsVfgyIWwB5Uv8QjujzY3C7pCfv9g06TcNZ3XzvBNmN4Cc6UgKhE3J34bhMzpj1siQHbUlGozGYVp5tbnycVMJSzy3o4prcKGeNYF+3J4Y=;4:0g+BJqTEOdBW7nzjtGYSJJe/EXjwoyeR4INCVDD1TA99SJmPV0xHEJdFl8cnHtJdkTqkMg4JM/VjDNe/RRmyFqMgh6/7dFjMxI6HUewtXPD+O30ldFB8+WoTUUKtQciKtGgswGLdSJfjOIUO8ymBtPSbjMsDd2T850cD7NeHhkxcaSSDCFuBFLwZyr+Foj0BO30B31B0FAYynQeNE73pr2gxV0zCjVVJCQOl6bLwXzx0Y3vzDuZApBBh4lM97SwNSWadgxBDe1Lv/JLwo6wt8rJ5SrLqhjm8uUzYfF8m8uxTn43nU1PWX/+O4FlD11nzrvhVkkyQ3riCxVfQsyCyCQ== X-Exchange-Antispam-Report-Test: UriScan:(60067363179207)(249562145798500); X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(100000700101)(100105000095)(100000701101)(100105300095)(100000702101)(100105100095)(6040450)(2401047)(5005006)(8121501046)(100000703101)(100105400095)(10201501046)(93006095)(93001095)(3002001)(6041248)(20161123562025)(20161123560025)(20161123564025)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(20161123558100)(20161123555025)(6072148)(201708071742011)(100000704101)(100105200095)(100000705101)(100105500095);SRVR:VI1PR08MB0749;BCL:0;PCL:0;RULEID:(100000800101)(100110000095)(100000801101)(100110300095)(100000802101)(100110100095)(100000803101)(100110400095)(100000804101)(100110200095)(100000805101)(100110500095);SRVR:VI1PR08MB0749; X-Forefront-PRVS: 0466CA5A45 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10019020)(6009001)(346002)(376002)(189002)(199003)(24454002)(106356001)(1076002)(9686003)(2906002)(50466002)(53936002)(101416001)(2950100002)(6116002)(54356999)(6916009)(229853002)(6246003)(105586002)(189998001)(68736007)(76176999)(3846002)(66066001)(4326008)(478600001)(47776003)(6306002)(305945005)(5660300001)(25786009)(50986999)(966005)(7736002)(55016002)(6506006)(33656002)(97736004)(69596002)(6666003)(53416004)(86362001)(316002)(16586007)(58126008)(81166006)(16526018)(81156014)(8676002)(83506002)(23686003)(93886005)(575784001)(8936002)(18370500001)(505234006);DIR:OUT;SFP:1102;SCL:1;SRVR:VI1PR08MB0749;H:outlook.office365.com;FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; X-Microsoft-Exchange-Diagnostics: =?koi8-r?Q?1;VI1PR08MB0749;23:wPbDnCRi5iT7dqkOl7/ptLZFob+ZFFQT8XZthURwyPx?= =?koi8-r?Q?iRYZGsZ5Slsq89KeaxLbGgOpbcU4UDU4ryurH1oe15d8xjdNbz43l1ZJkAtN/5?= =?koi8-r?Q?/Fl3U4BFI1Q4/0aiAx8nuWMkCar6yOdM5chj8+YCxcffEo1bqZhWMXS4CJiN/z?= =?koi8-r?Q?N9nhMOkULMLL21F0QFIV6D2kDDLaWv/OXyAC1VsTS4yAvkc3WeuNnTJ6/cc3uY?= =?koi8-r?Q?RNwfjA0B2dslvtCe/nM4T1IMfiVe0OwAk4wOswDQ5LSovdC5Uz6qrfvilsaaVx?= =?koi8-r?Q?vqKNIjVgY9KtmUFwvTRQUyYX/FE0zB0lJ0rG46+LNJ1P/iC+nkWWvWHYJuF9N8?= =?koi8-r?Q?R4XkH0wjjbqdH4M8YVKkTdEaMNKBpWmfZBiKD6CD/Ik//Bu4/pr4Eq0msnb3wq?= =?koi8-r?Q?A7wcQ+mfRb5vxzOIX6kYfWzGlAOySuArXHudrtmeCCBHiySUAS/a+6BD6815O1?= =?koi8-r?Q?7L4NBD/Qk7GycdSbf6UhudK+PZmTnqjzZNgS488BL5T1K5Y5bphc9jH7mLpn+C?= =?koi8-r?Q?H5l7NCNI5bEsEDhSe9JYB0fjOFhsZsDtm95BS7ewIdGUnoILKmaASMjLoFhDuM?= =?koi8-r?Q?5dqs6tdQ/mW+Ddrm5OG0ppb9tq1iaoKbiy4+MpCeZ5/byC3ZkYt4GmnO7KtrvW?= =?koi8-r?Q?kuiaK+JvNy/h6WH7cmCXw3igXNICdbp5OW6Re5wVw+rnLYCvKlAyANh4x60Moa?= =?koi8-r?Q?ZeW8x3mNCHePFloMufN9VjKFBMjRaTRo73UCEo2p35Q2lXTzQn+sOJykDrLmkJ?= =?koi8-r?Q?NCP3fIYu2Sq33Rb/Z1n/7u4AohK92dgHR5mayfHXhRrEbANHA+p/jvZiHlw2gD?= =?koi8-r?Q?xROl0FK+WW33miaMgFVWCfGcdtCQcirDn6JHl8/wAYeb0QrVbIwwRRNW8W55YB?= =?koi8-r?Q?mLBlsEti9nnbI83I/47H11xwPF5GLfCnuHeLYk64ZcjIhY/nX04sfESQiiGhWP?= =?koi8-r?Q?fubfFAppP114JWzX+YzflE2p0vqoVGitKk9MDi7MbYQKgESfbC5E2h/Y8HjNe8?= =?koi8-r?Q?CRdkCZppptfqtxxEnEI/QN+WTjj3S0hFQAvrjnHK8vHrlqk8hpCdE6La6fzFPt?= =?koi8-r?Q?VaoeENTPVSVvkh8zDltlbdgPuNAhIm44YK3z5N357ofVLVLejaBiNQp5DbGmFh?= =?koi8-r?Q?JUhGDbIboX/SNY8xdPKYcUX4lrYsIn93S9911BnLhxdE4FLxCI4nQzCrFPUvfo?= =?koi8-r?Q?QyqXHxRH95qbgQkubV9rk7n4L1FpO4AxPsvTIPhLAQch86xs3Ve4jNEfeGj2L7?= =?koi8-r?Q?nrTN4tLAlVHEANomZAJEXfyjJyAWp00oSU7kXypk=3D?= X-Microsoft-Exchange-Diagnostics: 1;VI1PR08MB0749;6:SW32Lk7pH5v2DWgrpU3di0sK/1awCTtRUrRW5dOp4lnIaGOnqO8c7XA/DIfRIJyreMEjqsnQhgepVAkfkWcopkZBkcS++lpIRq+77/YXhQ6kGezqWipt+jtrp428CM1o12eIyQuN0tmo234yTJy66TKio61Wh9Op+jBd1YLMrNYLHM03VQCdve+j6vD1/N/sFBBKpFJXLvWXxQ0GYo01kUr4KE8ieGQeCN4g2QrjVqAI1b76dDOFaWNVoX/JDXmjcPhMZUZx2LLXgkELLpLaUyOiWKbkyNmYmL+gPBveLbHPlQYTEtM/TBreW2Ds1Zd0GxW4JfvcCzi/CprNh0vLqw==;5:KmoHlsnyBF9ceQCLmLvghh4dod6Bug64ERpDzkujBsZlFSOVzbWMkFOmJGKy4eVgsYLAE43Oj46scxKl5okFBEfmVKK326KQUCiGXBOphve7YOHfoY/ZdfUFppMI9bKMH+2T3eDf4XN7KVcImYJvcA==;24:Ccha0ifmZP26C2MZUZw0cJOfWB6LlmMcldKsiRHkhi1bk98mbrur2M11+6yy0+DqaiMQqQgJZLGlBKeepYWZt+AWAppElMmNMLXUvBixwng=;7:rqLGVWju36mlHufpT2jk2sw7pVjvaDIFeUuW0A65I0yCm2TIO4QNfcaZ1V1YKt5T3PeI/TAE8Zv05m7IueoNGm7FNqCbAAH8mNUgN7Oeptez0YuMeiJPZUrggIh59GbZGD2NlJ9l3J7OMHm8pCjCciiQ0BeOsdJSBPvYIiNeWXU29JEFU6L+unJS8nsceUBzYIFnRz0oJcrSz9LF+dGBdkYHXuAUQplBg1KFLWuQmUc= SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-Microsoft-Exchange-Diagnostics: 1;VI1PR08MB0749;20:w5r/AbfsY5EukzZCL0pVdGcdKVFlH5OP2ThKNS+RBRJgGb3qwn7CzwLWyf1clfvk9DzpSEc3OseKWFQCCrZ1APILwPyTZ2EIofS8XXmpPLU/Sl3EDlO6wuepybqibNv03CHSCseTJhEH/QdZp7lFxV3ycZxa1cE5lW4BC0Hnzfo= X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Oct 2017 00:38:29.3662 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR08MB0749 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 19, 2017 at 03:35:22PM -0700, Andrei Vagin wrote: > On Thu, Oct 19, 2017 at 01:16:55PM -0500, Josh Poimboeuf wrote: > > On Thu, Oct 19, 2017 at 09:51:04AM -0700, Andrei Vagin wrote: > > > Hi, > > > > > > We run CRIU tests for tip/auto-latest regularly, and a few days ago our > > > test job started to detect this warning in a kernel log: > > > > > > [ 44.235786] WARNING: can't dereference iret registers at ffff8801c5f17fe0 for ip ffffffff95f0d94b > > > > > > What does it mean? How critical is it? > > > > > > Our test job fails if it detects any warning in a kernel log. Maybe we > > > need to investigate reasons of this warning and try to eliminate it? > > > > > > Here are logs: > > > https://travis-ci.org/avagin/linux/jobs/289676634 > > > > I think it means the unwinder found some bad ORC unwinder metadata. Any > > chance you have access to the kernel binary? I need to know what code > > corresponds to that ffffffff95f0d94b address. > > > > Or if you can reproduce with the following patch, that should help: > > > > > > diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c > > index 570b70d3f604..95b633f0ce51 100644 > > --- a/arch/x86/kernel/unwind_orc.c > > +++ b/arch/x86/kernel/unwind_orc.c > > @@ -448,7 +448,7 @@ bool unwind_next_frame(struct unwind_state *state) > > > > case ORC_TYPE_REGS_IRET: > > if (!deref_stack_regs(state, sp, &state->ip, &state->sp, false)) { > > - orc_warn("can't dereference iret registers at %p for ip %p\n", > > + orc_warn("can't dereference iret registers at %p for ip %pB\n", > > (void *)sp, (void *)orig_ip); > > goto done; > > } > > I applied your patch and rerun tests. > > [ 44.947699] WARNING: can't dereference iret registers at ffff880178f5ffe0 for ip int3+0x5b/0x60 > > and now here is a warning from kasan: > > [ 477.775676] ================================================================== > [ 477.775845] BUG: KASAN: stack-out-of-bounds in deref_stack_reg+0x11d/0x150 > [ 477.775952] Read of size 8 at addr ffff880166b7fe90 by task make/16028 > [ 477.776055] > [ 477.776149] CPU: 0 PID: 16028 Comm: make Not tainted 4.14.0-rc5+ #1 > [ 477.776152] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > [ 477.776155] Call Trace: > [ 477.776159] > [ 477.776167] dump_stack+0x5c/0x7e > [ 477.776175] print_address_description+0x6b/0x290 > [ 477.776182] ? deref_stack_reg+0x11d/0x150 > [ 477.776186] kasan_report+0x25d/0x340 > [ 477.776194] deref_stack_reg+0x11d/0x150 > [ 477.776201] ? __read_once_size_nocheck.constprop.6+0x10/0x10 > [ 477.776206] ? get_stack_info+0x37/0x170 > [ 477.776212] ? stack_access_ok+0xdc/0x150 > [ 477.776221] unwind_next_frame+0xe35/0x1c10 > [ 477.776230] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776238] ? deref_stack_reg+0x150/0x150 > [ 477.776247] ? is_bpf_text_address+0x54/0x60 > [ 477.776253] ? kernel_text_address+0xf4/0x100 > [ 477.776257] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776266] __save_stack_trace+0x73/0xd0 > [ 477.776277] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776285] save_stack+0x33/0xb0 > [ 477.776291] ? kasan_slab_free+0x70/0xc0 > [ 477.776298] ? kmem_cache_free+0x9f/0x230 > [ 477.776303] ? rcu_process_callbacks+0x451/0xd60 > [ 477.776307] ? __do_softirq+0x1d3/0x5e0 > [ 477.776312] ? irq_exit+0x146/0x170 > [ 477.776322] ? smp_apic_timer_interrupt+0x13e/0x3b0 > [ 477.776326] ? apic_timer_interrupt+0x8c/0xa0 > [ 477.776331] ? lock_acquire+0x6b/0x260 > [ 477.776336] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776347] ? update_curr+0x2d6/0x600 > [ 477.776354] ? posix_cpu_timers_exit_group+0x50/0x50 > [ 477.776365] ? trigger_load_balance+0x1fd/0x8a0 > [ 477.776374] ? note_gp_changes+0x14e/0x1b0 > [ 477.776384] ? lock_downgrade+0x590/0x590 > [ 477.776389] ? rcu_accelerate_cbs+0x106/0x5e0 > [ 477.776398] ? lock_acquire+0x113/0x260 > [ 477.776402] ? rcu_process_callbacks+0x407/0xd60 > [ 477.776407] kasan_slab_free+0x70/0xc0 > [ 477.776414] ? rcu_process_callbacks+0x451/0xd60 > [ 477.776418] kmem_cache_free+0x9f/0x230 > [ 477.776425] ? free_inode_nonrcu+0x20/0x20 > [ 477.776430] rcu_process_callbacks+0x451/0xd60 > [ 477.776443] ? note_gp_changes+0x1b0/0x1b0 > [ 477.776451] ? native_apic_msr_write+0x27/0x30 > [ 477.776456] ? lapic_next_event+0x55/0x80 > [ 477.776465] __do_softirq+0x1d3/0x5e0 > [ 477.776479] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776483] irq_exit+0x146/0x170 > [ 477.776487] smp_apic_timer_interrupt+0x13e/0x3b0 > [ 477.776494] apic_timer_interrupt+0x8c/0xa0 > [ 477.776497] > [ 477.776502] RIP: 0010:lock_acquire+0x6b/0x260 > [ 477.776505] RSP: 0018:ffff880166b7fd48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff11 > [ 477.776512] RAX: 0000000000000007 RBX: ffff8801c91cb080 RCX: 0000000000000000 > [ 477.776515] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801c91cb8b4 > [ 477.776518] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 > [ 477.776521] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > [ 477.776524] R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff9f651fce > [ 477.776528] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776552] do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776559] ? fs_reclaim_acquire.part.71+0x29/0x30 > [ 477.776564] ? fs_reclaim_acquire.part.71+0x5/0x30 > [ 477.776569] ? kmem_cache_alloc+0x29/0x1f0 > [ 477.776577] ? do_execveat_common.isra.34+0x78e/0x1890 > [ 477.776589] ? strncpy_from_user+0x74/0x260 > [ 477.776595] ? prepare_bprm_creds+0x100/0x100 > [ 477.776599] ? kmem_cache_alloc+0x18d/0x1f0 > [ 477.776607] ? getname_flags+0xff/0x500 > [ 477.776615] ? SyS_execve+0x2c/0x40 > [ 477.776623] ? ptregs_sys_vfork+0x10/0x10 > [ 477.776628] ? do_syscall_64+0x181/0x450 > [ 477.776638] ? entry_SYSCALL64_slow_path+0x25/0x25 > [ 477.776653] > [ 477.776747] The buggy address belongs to the page: > [ 477.776849] page:ffffea00059adfc0 count:0 mapcount:0 mapping: (null) index:0x0 > [ 477.776968] flags: 0x17fff8000000000() > [ 477.777067] raw: 017fff8000000000 0000000000000000 0000000000000000 00000000ffffffff > [ 477.777184] raw: 0000000000000000 dead000000000200 0000000000000000 0000000000000000 > [ 477.777298] page dumped because: kasan: bad access detected > [ 477.777404] > [ 477.777494] Memory state around the buggy address: > [ 477.777594] ffff880166b7fd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > [ 477.777709] ffff880166b7fe00: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 > [ 477.777823] >ffff880166b7fe80: f4 f4 f4 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 > [ 477.777937] ^ > [ 477.778034] ffff880166b7ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > [ 477.778147] ffff880166b7ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > [ 477.778260] ================================================================== > [ 477.778376] Disabling lock debugging due to kernel taint > > All logs are here https://travis-ci.org/avagin/linux/jobs/290190646 > > Unfortunately vmlinux was not saved for this run. Thanks. Here is vmlinux: https://www.dropbox.com/s/e70u6oxxj4pwe2h/vmlinux?dl=0