From patchwork Thu May 27 17:19:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 12284969 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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 27D6AC47089 for ; Thu, 27 May 2021 17:19:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC8BA613BE for ; Thu, 27 May 2021 17:19:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234277AbhE0RVO (ORCPT ); Thu, 27 May 2021 13:21:14 -0400 Received: from outbound-smtp29.blacknight.com ([81.17.249.32]:56307 "EHLO outbound-smtp29.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234911AbhE0RVN (ORCPT ); Thu, 27 May 2021 13:21:13 -0400 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp29.blacknight.com (Postfix) with ESMTPS id 2086518E03C for ; Thu, 27 May 2021 18:19:25 +0100 (IST) Received: (qmail 417 invoked from network); 27 May 2021 17:19:24 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.23.168]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 27 May 2021 17:19:24 -0000 Date: Thu, 27 May 2021 18:19:23 +0100 From: Mel Gorman To: Andrew Morton Cc: Andrii Nakryiko , Christoph Hellwig , Arnaldo Carvalho de Melo , Michal Suchanek , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , LKML , Jiri Olsa , Hritik Vijay , Linux-BPF , Linux-Net , Linux-MM Subject: [PATCH v3] mm/page_alloc: Require pahole v1.22 to cope with zero-sized struct pagesets Message-ID: <20210527171923.GG30378@techsingularity.net> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This patch replaces mm-page_alloc-convert-per-cpu-list-protection-to-local_lock-fix.patch in Andrew's tree. Michal Suchanek reported the following problem with linux-next [ 0.000000] Linux version 5.13.0-rc2-next-20210519-1.g3455ff8-vanilla (geeko@buildhost) (gcc (SUSE Linux) 10.3.0, GNU ld (GNU Binutils; openSUSE Tumbleweed) 2.36.1.20210326-3) #1 SMP Wed May 19 10:05:10 UTC 2021 (3455ff8) [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.13.0-rc2-next-20210519-1.g3455ff8-vanilla root=UUID=ec42c33e-a2c2-4c61-afcc-93e9527 8f687 plymouth.enable=0 resume=/dev/disk/by-uuid/f1fe4560-a801-4faf-a638-834c407027c7 mitigations=auto earlyprintk initcall_debug nomodeset earlycon ignore_loglevel console=ttyS0,115200 ... [ 26.093364] calling tracing_set_default_clock+0x0/0x62 @ 1 [ 26.098937] initcall tracing_set_default_clock+0x0/0x62 returned 0 after 0 usecs [ 26.106330] calling acpi_gpio_handle_deferred_request_irqs+0x0/0x7c @ 1 [ 26.113033] initcall acpi_gpio_handle_deferred_request_irqs+0x0/0x7c returned 0 after 3 usecs [ 26.121559] calling clk_disable_unused+0x0/0x102 @ 1 [ 26.126620] initcall clk_disable_unused+0x0/0x102 returned 0 after 0 usecs [ 26.133491] calling regulator_init_complete+0x0/0x25 @ 1 [ 26.138890] initcall regulator_init_complete+0x0/0x25 returned 0 after 0 usecs [ 26.147816] Freeing unused decrypted memory: 2036K [ 26.153682] Freeing unused kernel image (initmem) memory: 2308K [ 26.165776] Write protecting the kernel read-only data: 26624k [ 26.173067] Freeing unused kernel image (text/rodata gap) memory: 2036K [ 26.180416] Freeing unused kernel image (rodata/data gap) memory: 1184K [ 26.187031] Run /init as init process [ 26.190693] with arguments: [ 26.193661] /init [ 26.195933] with environment: [ 26.199079] HOME=/ [ 26.201444] TERM=linux [ 26.204152] BOOT_IMAGE=/boot/vmlinuz-5.13.0-rc2-next-20210519-1.g3455ff8-vanilla [ 26.254154] BPF: type_id=35503 offset=178440 size=4 [ 26.259125] BPF: [ 26.261054] BPF:Invalid offset [ 26.264119] BPF: [ 26.264119] [ 26.267437] failed to validate module [efivarfs] BTF: -22 Andrii Nakryiko bisected the problem to the commit "mm/page_alloc: convert per-cpu list protection to local_lock" currently staged in mmotm. In his own words The immediate problem is two different definitions of numa_node per-cpu variable. They both are at the same offset within .data..percpu ELF section, they both have the same name, but one of them is marked as static and another as global. And one is int variable, while another is struct pagesets. I'll look some more tomorrow, but adding Jiri and Arnaldo for visibility. [110907] DATASEC '.data..percpu' size=178904 vlen=303 ... type_id=27753 offset=163976 size=4 (VAR 'numa_node') type_id=27754 offset=163976 size=4 (VAR 'numa_node') [27753] VAR 'numa_node' type_id=27556, linkage=static [27754] VAR 'numa_node' type_id=20, linkage=global [20] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED [27556] STRUCT 'pagesets' size=0 vlen=1 'lock' type_id=507 bits_offset=0 [506] STRUCT '(anon)' size=0 vlen=0 [507] TYPEDEF 'local_lock_t' type_id=506 The patch in question introduces a zero-sized per-cpu struct and while this is not wrong, versions of pahole prior to 1.22 get confused during BTF generation with two separate variables occupying the same address. This patch adds a requirement for pahole 1.22 before setting DEBUG_INFO_BTF. While pahole 1.22 does not exist yet, a fix is in the pahole git tree as ("btf_encoder: fix and complete filtering out zero-sized per-CPU variables"). Reported-by: Michal Suchanek Reported-by: Hritik Vijay Debugged-by: Andrii Nakryiko Signed-off-by: Mel Gorman --- lib/Kconfig.debug | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 678c13967580..825be101767e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -301,10 +301,14 @@ config DEBUG_INFO_DWARF5 endchoice # "DWARF version" +config PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT + def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "122") + config DEBUG_INFO_BTF bool "Generate BTF typeinfo" depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST + depends on PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT help Generate deduplicated BTF type information from DWARF debug info. Turning this on expects presence of pahole tool, which will convert