From patchwork Tue Feb 9 07:10:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gow X-Patchwork-Id: 380498 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 DB5DEC433E0 for ; Tue, 9 Feb 2021 07:11:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E0EF64DB3 for ; Tue, 9 Feb 2021 07:11:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230058AbhBIHL2 (ORCPT ); Tue, 9 Feb 2021 02:11:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230043AbhBIHLX (ORCPT ); Tue, 9 Feb 2021 02:11:23 -0500 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5CBAC061786 for ; Mon, 8 Feb 2021 23:10:41 -0800 (PST) Received: by mail-pf1-x44a.google.com with SMTP id w67so10427386pfd.5 for ; Mon, 08 Feb 2021 23:10:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=hKso1MwLRLw8n4+Grqq4tnQrzP51F50oX7aHEUrMrFI=; b=Bb5HKfqMvcuXwLRKuIc/nM60N7hDs2c47YYZ6XuJx8vUW9hQmNBlsZdudbUsOmTt9W 25NVlfcONEgRGyjPOq7wb9lgFVq5lQ8IVBO4SrLEDCAHfnFUfJLP88AmiZ6ko4xj+zv1 J8NH5Z5F3fOuurrK6m9dEBIf0AE1jLI0esPgKg2+6ujWAFc/CIdL88E5zXEimKNtef48 FFnGOa4H0V5cULMnyJUpzW9rKH6nwmhl/g9jIn0YoW21jojQ2Nd7M7hHvMNsUKu5nbdL p16B6NjKKIltD23f7gmZByI1PbrSufoLBm9z/Yt6yUeqerwNf/y1L2iPUXje+Z5DKnKr sn6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=hKso1MwLRLw8n4+Grqq4tnQrzP51F50oX7aHEUrMrFI=; b=qSwop8gQyGCpOqAiCJvZbYKlG5Zk+bc9QsNtkhKzH8b919PRTQobiiLQcHOvXf2Nju hvbl1rg7o5U8RfaWKccdN6zXqjDqQ2IuO8hM8sotBeCNlO/a5tyNgskVf/cSR+ERR0xx sjh8j4MKK2ILYURUI8mZzutvZGlIZ8KkUO3wtJxiBrg9XIBMkNVHvCvv3nHYb7qTci3u Q1+jFs00PitvRS7owGXGI5AZa6tvVAx5cAAlB9fU+pajZhfNXjJKiI1h4HRABdgQCD55 QDSC7svUqXhJEEINlxisnwBtCHvWeAT5ojKdaza5FQ/S4+PFSO/HmiBiMZywa3IJCpcK UH1Q== X-Gm-Message-State: AOAM533SbkT76icT3HSQkJ6wN20IR37YxUCk3WuPNQrUKtKgHFjbOIlQ FyJwNpWFukPZ/pty9Y6FHGXXS8c2O5Zezw== X-Google-Smtp-Source: ABdhPJz2uyZNOUWxCh8+bTaw0WF2AyuBjDmjriJxozzN+RmdDvksIBD9JocSbE0wQEhImCMlRxv9hoQdlniMiQ== Sender: "davidgow via sendgmr" X-Received: from spirogrip.svl.corp.google.com ([2620:15c:2cb:201:e4e6:62d4:a840:252a]) (user=davidgow job=sendgmr) by 2002:aa7:98d2:0:b029:1da:3374:4777 with SMTP id e18-20020aa798d20000b02901da33744777mr13937516pfm.45.1612854641040; Mon, 08 Feb 2021 23:10:41 -0800 (PST) Date: Mon, 8 Feb 2021 23:10:34 -0800 Message-Id: <20210209071034.3268897-1-davidgow@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog Subject: [PATCH] kunit: tool: Disable PAGE_POISONING under --alltests From: David Gow To: Brendan Higgins , Shuah Khan , Vlastimil Babka Cc: David Gow , kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, linux-um@lists.infradead.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org kunit_tool maintains a list of config options which are broken under UML, which we exclude from an otherwise 'make ARCH=um allyesconfig' build used to run all tests with the --alltests option. Something in UML allyesconfig is causing segfaults when page poisining is enabled (and is poisoning with a non-zero value). Previously, this didn't occur, as allyesconfig enabled the CONFIG_PAGE_POISONING_ZERO option, which worked around the problem by zeroing memory. This option has since been removed, and memory is now poisoned with 0xAA, which triggers segfaults in many different codepaths, preventing UML from booting. Note that we have to disable both CONFIG_PAGE_POISONING and CONFIG_DEBUG_PAGEALLOC, as the latter will 'select' the former on architectures (such as UML) which don't implement __kernel_map_pages(). Ideally, we'd fix this properly by tracking down the real root cause, but since this is breaking KUnit's --alltests feature, it's worth disabling there in the meantime so the kernel can boot to the point where tests can actually run. Fixes: f289041ed4 ("mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO") Signed-off-by: David Gow Reviewed-by: Brendan Higgins --- As described above, 'make ARCH=um allyesconfig' is broken. KUnit has been maintaining a list of configs to force-disable for this in tools/testing/kunit/configs/broken_on_uml.config. The kernels we've built with this have broken since CONFIG_PAGE_POISONING_ZERO was removed, panic-ing on startup with: <0>[ 0.100000][ T11] Kernel panic - not syncing: Segfault with no mm <4>[ 0.100000][ T11] CPU: 0 PID: 11 Comm: kdevtmpfs Not tainted 5.11.0-rc7-00003-g63381dc6f5f1-dirty #4 <4>[ 0.100000][ T11] Stack: <4>[ 0.100000][ T11] 677d3d40 677d3f10 0000000e 600c0bc0 <4>[ 0.100000][ T11] 677d3d90 603c99be 677d3d90 62529b93 <4>[ 0.100000][ T11] 603c9ac0 677d3f10 62529b00 603c98a0 <4>[ 0.100000][ T11] Call Trace: <4>[ 0.100000][ T11] [<600c0bc0>] ? set_signals+0x0/0x60 <4>[ 0.100000][ T11] [<603c99be>] lookup_mnt+0x11e/0x220 <4>[ 0.100000][ T11] [<62529b93>] ? down_write+0x93/0x180 <4>[ 0.100000][ T11] [<603c9ac0>] ? lock_mount+0x0/0x160 <4>[ 0.100000][ T11] [<62529b00>] ? down_write+0x0/0x180 <4>[ 0.100000][ T11] [<603c98a0>] ? lookup_mnt+0x0/0x220 <4>[ 0.100000][ T11] [<603c8160>] ? namespace_unlock+0x0/0x1a0 <4>[ 0.100000][ T11] [<603c9b25>] lock_mount+0x65/0x160 <4>[ 0.100000][ T11] [<6012f360>] ? up_write+0x0/0x40 <4>[ 0.100000][ T11] [<603cbbd2>] do_new_mount_fc+0xd2/0x220 <4>[ 0.100000][ T11] [<603eb560>] ? vfs_parse_fs_string+0x0/0xa0 <4>[ 0.100000][ T11] [<603cbf04>] do_new_mount+0x1e4/0x260 <4>[ 0.100000][ T11] [<603ccae9>] path_mount+0x1c9/0x6e0 <4>[ 0.100000][ T11] [<603a9f4f>] ? getname_kernel+0xaf/0x1a0 <4>[ 0.100000][ T11] [<603ab280>] ? kern_path+0x0/0x60 <4>[ 0.100000][ T11] [<600238ee>] 0x600238ee <4>[ 0.100000][ T11] [<62523baa>] devtmpfsd+0x52/0xb8 <4>[ 0.100000][ T11] [<62523b58>] ? devtmpfsd+0x0/0xb8 <4>[ 0.100000][ T11] [<600fffd8>] kthread+0x1d8/0x200 <4>[ 0.100000][ T11] [<600a4ea6>] new_thread_handler+0x86/0xc0 Disabling PAGE_POISONING fixes this. The issue can't be repoduced with just PAGE_POISONING, there's clearly something (or several things) also enabled by allyesconfig which contribute. Ideally, we'd track these down and fix this at its root cause, but in the meantime it'd be nice to disable PAGE_POISONING so we can at least get the kernel to boot. One way would be to add a 'depends on !UML' or similar, but since PAGE_POISONING does seem to work in the non-allyesconfig case, adding it to our list of broken configs seemed the better choice. Thoughts? (Note that to reproduce this, you'll want to run ./tools/testing/kunit/kunit.py run --alltests --raw_output It also depends on a couple of other fixes which are not upstream yet: https://www.spinics.net/lists/linux-rtc/msg08294.html https://lore.kernel.org/linux-i3c/20210127040636.1535722-1-davidgow@google.com/ Cheers, -- David tools/testing/kunit/configs/broken_on_uml.config | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/kunit/configs/broken_on_uml.config b/tools/testing/kunit/configs/broken_on_uml.config index a7f0603d33f6..690870043ac0 100644 --- a/tools/testing/kunit/configs/broken_on_uml.config +++ b/tools/testing/kunit/configs/broken_on_uml.config @@ -40,3 +40,5 @@ # CONFIG_RESET_BRCMSTB_RESCAL is not set # CONFIG_RESET_INTEL_GW is not set # CONFIG_ADI_AXI_ADC is not set +# CONFIG_DEBUG_PAGEALLOC is not set +# CONFIG_PAGE_POISONING is not set