From patchwork Wed Apr 3 13:19:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 13616101 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E3AB7CD128A for ; Wed, 3 Apr 2024 13:19:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 16DC210FE38; Wed, 3 Apr 2024 13:19:44 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="Vq0LkGiI"; dkim-atps=neutral Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8714210FB98 for ; Wed, 3 Apr 2024 13:19:42 +0000 (UTC) Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-1e27f800ad0so11066245ad.1 for ; Wed, 03 Apr 2024 06:19:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1712150381; x=1712755181; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:from:to:cc:subject:date:message-id:reply-to; bh=5jeOyVY2AHqhv0KvV6kieVXey6Da3SBwUwdCTK976WY=; b=Vq0LkGiIMyt5HiXpciU8vJ8H1XRQ7VNg7QKlQnVkxaN3iSUoBuwwc6W3pPC4285AZ4 HkGHXlpWPLrS6/62nRA4rp/OZKLmjlIp1sP4gnH/U/m9L0aVPhQJO9zldJsKnx+YDeel cMxGWefVsKGviQ+w5c61lHYiGrQCgm85wyI2C3nNlza4oUCiXYs8Oc+o8E+BQ8x3chLZ JJZm3XFtwl0oQraV0pE8562ZGGhv2FM6N/f3dzZsmj+t5xUqSeTa9GTfqCs3f0PPGbtS CFgzq47mhs36djiF9XLXAGlgiVEEeTM8+ba/n8WrWJsAvuBLhDr4HGP84Z03GWFt5oT6 2A4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712150381; x=1712755181; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=5jeOyVY2AHqhv0KvV6kieVXey6Da3SBwUwdCTK976WY=; b=pXWVh95oJkIpManu1BPfHYrvJhWjkgKbD1i65tQNb+LE31khcKTPuaxYc4ZbkhxUE9 aYuZiZfKjT3/CUKkOf78Rwpscfipn4rV5wYRXk19GDSq+1FwLIWA1HvyGRct83Ma+ELU Hg2W27hcSCCF9GCnWln11FiC33jcbdMYu+bMUacQOkKm4HYJ2usD/vO2vNq3YAp2M6Fb 0ZIsR08KA6lZUlv6Q3TLB0uYDuJxVIs4ZBxY8Q8l74FpLUwyprjV1dkM3kyl1B5mtzf0 byoFZLCbqzizNkUhrHb6JXGHofDlLjb5LuSCi9VFgSbhqkVNmE4xL4+MMJBZETRdnEcT n5CQ== X-Forwarded-Encrypted: i=1; AJvYcCUFm9lMl+SIKf6raTyb3X58CtlCBIJ95wp7VayiMSUvVRfjPXD+Vit2QIBylboDTelzlHflM1M6OHUIvHgYQC/PuaquV7fcZDsaVWlhAGkZ X-Gm-Message-State: AOJu0YzkG6djZ5TIQ3dTsU4QmQ2/bfjTw2salyrTZlOqLec+D2k2fsQm Al9ZPBHzxPOJ4h/kUu67RBG+Eja+kbez88v5AV5cKH7GGU+P2qiK X-Google-Smtp-Source: AGHT+IGUUHIUOOsCxCF/TsSf8IWxMRQa7fBTBtgLaZOyDBRCO0Z9+JW6g9cTcLQ9TLR427e8GbHcQA== X-Received: by 2002:a17:902:f68b:b0:1e2:8ec0:90c4 with SMTP id l11-20020a170902f68b00b001e28ec090c4mr2621403plg.2.1712150381396; Wed, 03 Apr 2024 06:19:41 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id p2-20020a170902780200b001e00e17c6e2sm13430178pll.138.2024.04.03.06.19.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Apr 2024 06:19:40 -0700 (PDT) From: Guenter Roeck To: linux-kselftest@vger.kernel.org Cc: David Airlie , Arnd Bergmann , =?utf-8?q?Ma=C3=ADra_Canal?= , Dan Carpenter , Kees Cook , Daniel Diaz , David Gow , Arthur Grillo , Brendan Higgins , Naresh Kamboju , Maarten Lankhorst , Andrew Morton , Maxime Ripard , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , Daniel Vetter , Thomas Zimmermann , dri-devel@lists.freedesktop.org, kunit-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, loongarch@lists.linux.dev, netdev@vger.kernel.org, x86@kernel.org, Guenter Roeck Subject: [PATCH v3 00/15] Add support for suppressing warning backtraces Date: Wed, 3 Apr 2024 06:19:21 -0700 Message-Id: <20240403131936.787234-1-linux@roeck-us.net> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Some unit tests intentionally trigger warning backtraces by passing bad parameters to kernel API functions. Such unit tests typically check the return value from such calls, not the existence of the warning backtrace. Such intentionally generated warning backtraces are neither desirable nor useful for a number of reasons. - They can result in overlooked real problems. - A warning that suddenly starts to show up in unit tests needs to be investigated and has to be marked to be ignored, for example by adjusting filter scripts. Such filters are ad-hoc because there is no real standard format for warnings. On top of that, such filter scripts would require constant maintenance. One option to address problem would be to add messages such as "expected warning backtraces start / end here" to the kernel log. However, that would again require filter scripts, it might result in missing real problematic warning backtraces triggered while the test is running, and the irrelevant backtrace(s) would still clog the kernel log. Solve the problem by providing a means to identify and suppress specific warning backtraces while executing test code. Support suppressing multiple backtraces while at the same time limiting changes to generic code to the absolute minimum. Architecture specific changes are kept at minimum by retaining function names only if both CONFIG_DEBUG_BUGVERBOSE and CONFIG_KUNIT are enabled. The first patch of the series introduces the necessary infrastructure. The second patch introduces support for counting suppressed backtraces. This capability is used in patch three to implement unit tests. Patch four documents the new API. The next two patches add support for suppressing backtraces in drm_rect and dev_addr_lists unit tests. These patches are intended to serve as examples for the use of the functionality introduced with this series. The remaining patches implement the necessary changes for all architectures with GENERIC_BUG support. With CONFIG_KUNIT enabled, image size increase with this series applied is approximately 1%. The image size increase (and with it the functionality introduced by this series) can be avoided by disabling CONFIG_KUNIT_SUPPRESS_BACKTRACE. This series is based on the RFC patch and subsequent discussion at https://patchwork.kernel.org/project/linux-kselftest/patch/02546e59-1afe-4b08-ba81-d94f3b691c9a@moroto.mountain/ and offers a more comprehensive solution of the problem discussed there. Design note: Function pointers are only added to the __bug_table section if both CONFIG_KUNIT_SUPPRESS_BACKTRACE and CONFIG_DEBUG_BUGVERBOSE are enabled to avoid image size increases if CONFIG_KUNIT is disabled. There would be some benefits to adding those pointers all the time (reduced complexity, ability to display function names in BUG/WARNING messages). That change, if desired, can be made later. Checkpatch note: Remaining checkpatch errors and warnings were deliberately ignored. Some are triggered by matching coding style or by comments interpreted as code, others by assembler macros which are disliked by checkpatch. Suggestions for improvements are welcome. Changes since RFC: - Introduced CONFIG_KUNIT_SUPPRESS_BACKTRACE - Minor cleanups and bug fixes - Added support for all affected architectures - Added support for counting suppressed warnings - Added unit tests using those counters - Added patch to suppress warning backtraces in dev_addr_lists tests Changes since v1: - Rebased to v6.9-rc1 - Added Tested-by:, Acked-by:, and Reviewed-by: tags [I retained those tags since there have been no functional changes] - Introduced KUNIT_SUPPRESS_BACKTRACE configuration option, enabled by default. Changes since v2: - Rebased to v6.9-rc2 - Added comments to drm warning suppression explaining why it is needed. - Added patch to move conditional code in arch/sh/include/asm/bug.h to avoid kerneldoc warning - Added architecture maintainers to Cc: for architecture specific patches - No functional changes ---------------------------------------------------------------- Guenter Roeck (15): bug/kunit: Core support for suppressing warning backtraces kunit: bug: Count suppressed warning backtraces kunit: Add test cases for backtrace warning suppression kunit: Add documentation for warning backtrace suppression API drm: Suppress intentional warning backtraces in scaling unit tests net: kunit: Suppress lock warning noise at end of dev_addr_lists tests x86: Add support for suppressing warning backtraces arm64: Add support for suppressing warning backtraces loongarch: Add support for suppressing warning backtraces parisc: Add support for suppressing warning backtraces s390: Add support for suppressing warning backtraces sh: Add support for suppressing warning backtraces sh: Move defines needed for suppressing warning backtraces riscv: Add support for suppressing warning backtraces powerpc: Add support for suppressing warning backtraces Documentation/dev-tools/kunit/usage.rst | 30 ++++++++- arch/arm64/include/asm/asm-bug.h | 29 ++++++--- arch/arm64/include/asm/bug.h | 8 ++- arch/loongarch/include/asm/bug.h | 38 ++++++++---- arch/parisc/include/asm/bug.h | 29 ++++++--- arch/powerpc/include/asm/bug.h | 37 +++++++++--- arch/riscv/include/asm/bug.h | 38 ++++++++---- arch/s390/include/asm/bug.h | 17 +++++- arch/sh/include/asm/bug.h | 28 +++++++-- arch/x86/include/asm/bug.h | 21 +++++-- drivers/gpu/drm/tests/drm_rect_test.c | 16 +++++ include/asm-generic/bug.h | 16 ++++- include/kunit/bug.h | 56 +++++++++++++++++ include/kunit/test.h | 1 + include/linux/bug.h | 13 ++++ lib/bug.c | 51 ++++++++++++++-- lib/kunit/Kconfig | 9 +++ lib/kunit/Makefile | 7 ++- lib/kunit/backtrace-suppression-test.c | 104 ++++++++++++++++++++++++++++++++ lib/kunit/bug.c | 42 +++++++++++++ net/core/dev_addr_lists_test.c | 6 ++ 21 files changed, 524 insertions(+), 72 deletions(-) create mode 100644 include/kunit/bug.h create mode 100644 lib/kunit/backtrace-suppression-test.c create mode 100644 lib/kunit/bug.c Tested-by: Kees Cook