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 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 7E372E674B5 for ; Mon, 22 Dec 2025 14:00:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F2C4F10E6A6; Mon, 22 Dec 2025 14:00:39 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="BzEMpXFT"; dkim-atps=neutral Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6743510E5D4 for ; Mon, 22 Dec 2025 08:29:14 +0000 (UTC) Received: by mail-pf1-f194.google.com with SMTP id d2e1a72fcca58-7baf61be569so4011547b3a.3 for ; Mon, 22 Dec 2025 00:29:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1766392154; x=1766996954; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=UJ0Fy32CNz68gAtuvvvAIFbPIlI5INll01DQrP39TKA=; b=BzEMpXFTFU8IUBuFSp2ZvKv8D63DrBLIagh6mlVtUBtsW3gwi4oxzGlHCOOgmIN2+a 5Y+5Dmud4FTOpJKXrc1pDGXFgfw1RpgnVfrIMf87PhmNpH88y4VoWe6DlKAIwprYFqFM tifZ9fWdiB9NKKXox2210eyQqWHTQBGMCAU1Z8XLM/wYsaDlHPhvPQLiIE/36wiE+giD W+xXxjMTEd1XZyBqDgor2oXCf9bFT6XdoV5+RUblqtTdu/mRLJu5eaGjYKVW70mV5xQE 2+cg++oqSspi43PqF4ODb39At8RChGpIaV/tKlAG7cT16XH9WIxAiHd7qGosnQO7LT/2 n8Dg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766392154; x=1766996954; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=UJ0Fy32CNz68gAtuvvvAIFbPIlI5INll01DQrP39TKA=; b=pLGtvM4Qyxs7FLCjIQFfi8DZCIs3+P57CCm4eEMsysNdlVI+IKid6cE4oKzxV2hxLJ ho7vOH9GSwDyIrA7G2J8LZJM4KcSzWJnW9xJS/EDZqELenDRayWcG2HFPM06GhPNVyni bNl0C2z8gXdIdPHi+i8SHkYLZ9kBYDODYwwqJzcqjmn0ho8iUka/3vugj1tHxZUo14f6 QLRuP2LMtqtp8eXUWtPhqICQA97cwk/T+NiW5cehz18sY8Bp3ijQ5bYslvw9BHiGb4MR E6eCyEDWBN5MP4qJYxQdRas9P3+iBATiSN2NLyrQPbmpjRbm1/INRqThHWnfd0xmY0wg T4hw== X-Forwarded-Encrypted: i=1; AJvYcCU9jGGpyH/Rmhw6uO4oTmkscbaAr7PrBM911Fx3zHw4DFjx47P4U6wMUoCS7BJhwiLkoUvLQnHArmA=@lists.freedesktop.org X-Gm-Message-State: AOJu0YzJcxNwT32BXIbgppsPfm7rUl2gcQYeBz45afS8jhZ79i/SVOf+ 1FoyL57FM68xetM+oUT1N94hmuXe5AQ4s1dfC34gg0sakx/4KUOaq36G X-Gm-Gg: AY/fxX4HQ13BIVV7zU3Zqg0FmqvIaQ6pIIb2ffESOUJ+4ZfAK5xkLRMmWlcGH7GlPNU 5zBpH5b7lanPdR2y9TWayKA6ub8BFxPTFrrOLJZHFoBphgAUPJZtum2tmlPmHD9JstvzYSqeSIF LRlCMTAFCY9v5PX7dzW7sI1cJQ+JhOG06xgO768FrTXRLOxM2UOtx9yFQct8Wp8pY7iaazwi54F HC/QGh0wZz5BsuMvRTEfzHRVEWMBcWH+1w9hxfKdLEc8+jdfakaohZqjCurZEdf8+DPUS3Wubdj FQvrfnYgr+rO0H+1NcZP2BSIEG3yOx9ejPl6TYbo1RNfD2xK9aGgXuZU+96aYj/oPzxs8ILNIcr i+zV5VIzDAopDtR9q9U+uCkbmnsG3RhKN/9JgevpuPK74pnCd9/8Mugeb2JLNKyL0p2aZKJzLWI 8EDhmxtmsH X-Google-Smtp-Source: AGHT+IH91xYoqgoO/9cTyIkcwq8ylRSPWssYXk7Ak1UGNvKWMh8b4fE0tkVyhdkLY2d/CPzf+gHPIA== X-Received: by 2002:a05:6a00:1f17:b0:7f1:fad7:2ce with SMTP id d2e1a72fcca58-7ff679669d1mr11073286b3a.48.1766392153873; Mon, 22 Dec 2025 00:29:13 -0800 (PST) Received: from frodo ([2404:4400:417e:3d00:8b90:7f55:1261:772f]) by smtp.googlemail.com with ESMTPSA id d2e1a72fcca58-7ff7af29dcfsm9640064b3a.17.2025.12.22.00.29.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Dec 2025 00:29:13 -0800 (PST) From: Jim Cromie To: linux-kernel@vger.kernel.org, jbaron@akamai.com, gregkh@linuxfoundation.org, ukaszb@chromium.org, louis.chauvet@bootlin.com Cc: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, daniel.vetter@ffwll.ch, tvrtko.ursulin@linux.intel.com, jani.nikula@intel.com, ville.syrjala@linux.intel.com, seanpaul@chromium.org, robdclark@gmail.com, groeck@google.com, yanivt@google.com, bleung@google.com, quic_saipraka@quicinc.com, will@kernel.org, catalin.marinas@arm.com, quic_psodagud@quicinc.com, maz@kernel.org, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, mingo@redhat.com, jim.cromie@gmail.com Subject: [PATCH v7 00/31] drm/dyndbg: Fix dynamic debug classmap regression Date: Mon, 22 Dec 2025 21:28:12 +1300 Message-ID: <20251222082843.1816701-1-jim.cromie@gmail.com> X-Mailer: git-send-email 2.52.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Mon, 22 Dec 2025 14:00:06 +0000 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" hello all, commit aad0214f3026 ("dyndbg: add DECLARE_DYNDBG_CLASSMAP macro") added dyndbg's "classmaps" feature, which brought dyndbg's 0-off-cost debug to DRM. Dyndbg wired to /sys/module/drm/parameters/debug, mapped its bits to classes named "DRM_UT_*", and effected the callsite enablements only on updates to the sys-node (and underlying >control). Sadly, it hit a CI failure, resulting in: commit bb2ff6c27bc9 ("drm: Disable dynamic debug as broken") The regression was that drivers, when modprobed, did not get the drm.debug=0xff turn-on action, because that had already been done for drm.ko itself. The core design bug is in the DECLARE_DYNDBG_CLASSMAP macro. Its use in both drm.ko (ie core) and all drivers.ko meant that they couldn't fundamentally distinguish their respective roles. They each "re-defined" the classmap separately, breaking K&R-101. My ad-hoc test scripting helped to hide the error from me, by 1st testing various combos of boot-time module.dyndbg=... and drm.debug=... configurations, and then inadvertently relying upon those initializations. This series addresses both failings: It replaces DECLARE_DYNDBG_CLASSMAP with - `DYNAMIC_DEBUG_CLASSMAP_DEFINE`: Used by core modules (e.g., `drm.ko`) to define their classmaps. Based upon DECLARE, it exports the classmap so USE can use it. - `DYNAMIC_DEBUG_CLASSMAP_USE`: this lets other "subsystem" users create a linkage to the classmap defined elsewhere (ie drm.ko). These users can then find their "parent" and apply its settings. It adds a selftest script, and a 2nd "sub-module" to recapitulate DRM's multi-module "subsystem" use-case, including the specific failure scenario. It also adds minor parsing enhancements, allowing easier construction of multi-part debug configurations. These enhancements are used to test classmaps in particular, but are not otherwize required. v7 adds: . WARN_ONCE when classmap isnt found for a class'd callsite, JBaron . reorder macro args to match kdoc, JBaron . Doc formatting fixes, by Bagas Thank you for your review. P.S. Id also like to "tease" some other work: 1. patchset to send pr_debugs to tracefs on +T flag allows 63 "private" tracebufs, 1 "common" one (at 0) "drm.debug_2trace=0x1ff" is possible from Lukas Bartoski 2. patchset to save 40% of DATA_DATA footprint move (modname,filename,function) to struct _ddebug_site save their descriptor intervals to 3 maple-trees 3 accessors fetch on descriptor, from trees move __dyndbg_sites __section to INIT_DATA 3. patchset to cache dynamic-prefixes should hide 2.s cost increase. Jim Cromie (31): fixes, cleanups, simple stuff:: Jim Cromie (31): dyndbg: factor ddebug_match_desc out from ddebug_change dyndbg: add stub macro for DECLARE_DYNDBG_CLASSMAP docs/dyndbg: update examples \012 to \n docs/dyndbg: explain flags parse 1st test-dyndbg: fixup CLASSMAP usage error dyndbg: reword "class unknown," to "class:_UNKNOWN_" dyndbg: make ddebug_class_param union members same size dyndbg: drop NUM_TYPE_ARRAY dyndbg: tweak pr_fmt to avoid expansion conflicts dyndbg: reduce verbose/debug clutter callchain grooming, re-structs, code simplify/dedup by macros:: dyndbg: refactor param_set_dyndbg_classes and below dyndbg: tighten fn-sig of ddebug_apply_class_bitmap dyndbg: replace classmap list with a vector dyndbg: macrofy a 2-index for-loop pattern dyndbg,module: make proper substructs in _ddebug_info dyndbg: hoist classmap-filter-by-modname up to ddebug_add_module dyndbg: move mod_name down from struct ddebug_table to _ddebug_info dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code selftests-dyndbg: add a dynamic_debug run_tests target dyndbg: change __dynamic_func_call_cls* macros into expressions core fix, detect api misuse errors, etc:: dyndbg-API: replace DECLARE_DYNDBG_CLASSMAP dyndbg: detect class_id reservation conflicts dyndbg: check DYNAMIC_DEBUG_CLASSMAP_DEFINE args at compile-time dyndbg-test: change do_prints testpoint to accept a loopct dyndbg-API: promote DYNAMIC_DEBUG_CLASSMAP_PARAM to API dyndbg: treat comma as a token separator dyndbg: split multi-query strings with % selftests-dyndbg: add test_mod_submod dyndbg: resolve "protection" of class'd pr_debug dyndbg: add DYNAMIC_DEBUG_CLASSMAP_USE_(dd_class_name, offset) docs/dyndbg: add classmap info to howto .../admin-guide/dynamic-debug-howto.rst | 187 ++++- MAINTAINERS | 3 +- include/asm-generic/vmlinux.lds.h | 5 +- include/linux/dynamic_debug.h | 302 +++++-- kernel/module/main.c | 15 +- lib/Kconfig.debug | 24 +- lib/Makefile | 5 + lib/dynamic_debug.c | 776 +++++++++++------- lib/test_dynamic_debug.c | 198 +++-- lib/test_dynamic_debug_submod.c | 21 + tools/testing/selftests/Makefile | 1 + .../testing/selftests/dynamic_debug/Makefile | 9 + tools/testing/selftests/dynamic_debug/config | 7 + .../dynamic_debug/dyndbg_selftest.sh | 373 +++++++++ 14 files changed, 1465 insertions(+), 461 deletions(-) create mode 100644 lib/test_dynamic_debug_submod.c create mode 100644 tools/testing/selftests/dynamic_debug/Makefile create mode 100644 tools/testing/selftests/dynamic_debug/config create mode 100755 tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh -- 2.52.0