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[98.38.17.99]) by smtp.googlemail.com with ESMTPSA id 5614622812f47-4673434a35csm4795987b6e.20.2026.03.13.06.24.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Mar 2026 06:24:06 -0700 (PDT) From: Jim Cromie To: airlied@gmail.com, simona@ffwll.ch, jbaron@akamai.com, gregkh@linuxfoundation.org, Jim Cromie , Andrew Morton , linux-kernel@vger.kernel.org Cc: mripard@kernel.org, tzimmermann@suse.de, maarten.lankhorst@linux.intel.com, jani.nikula@intel.com, ville.syrjala@linux.intel.com, christian.koenig@amd.com, matthew.auld@intel.com, arunpravin.paneerselvam@amd.com, louis.chauvet@bootlin.com, skhan@linuxfoundation.org, pmladek@suse.com, ukaszb@chromium.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, amd-gfx@lists.freedesktop.org Subject: [PATCH v11 32/65] dyndbg: Harden classmap and callsite validation Date: Fri, 13 Mar 2026 07:19:57 -0600 Message-ID: <20260313132103.2529746-33-jim.cromie@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260313132103.2529746-1-jim.cromie@gmail.com> References: <20260313132103.2529746-1-jim.cromie@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Dynamic debug classmaps allow modules to _DEFINE or _USE classmaps, which map classnames to a range of class-IDs (0..62) that they are using. This names =3D> IDs mapping allows many modules to use 0..N independently, and even allows (carefully) shared classnames. Previously, class validation only caught some violations in _DEFINEd classmaps; 0..62 range checks, overlaps among _DEFINEd classmaps, but left blind spots in _USEs, for out of bounds manual offsets, overlapping _USEd classmaps, unknown map types, and orphaned callsite IDs. These oversights could lead to ambiguous routing or spammy warnings during control query execution. This commit hardens classmap and descriptor validation: - Mirror the compile-time limits of _DEFINE by adding a static_assert to validate the _offset value passed to DYNAMIC_DEBUG_CLASSMAP_USE_. - Add run-time overlap checks for _USEd classmaps in ddebug_add_module() to prevent collisions between private maps and imported APIs. - Validate that module classmaps use known enum map types. - Scan module descriptors at load time to print a single warning per missing class_id, rather than waiting for a user query to trip over it. - Downgrade the global WARN_ONCE in ddebug_match_desc() to a pr_warn_ratelimited, since orphaned class IDs are now tracked and warned about early at module load. Signed-off-by: Jim Cromie --- include/linux/dynamic_debug.h | 2 ++ lib/dynamic_debug.c | 52 +++++++++++++++++++++++++++++++---- 2 files changed, 48 insertions(+), 6 deletions(-) diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 0d1245aefc69..28684cfc0937 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -262,6 +262,8 @@ struct _ddebug_class_param { =20 #define __DYNAMIC_DEBUG_CLASSMAP_USE(_var, _offset, _uname) \ extern struct _ddebug_class_map _var; \ + static_assert((_offset) >=3D 0 && (_offset) < _DPRINTK_CLASS_DFLT, \ + "classmap use offset must be in 0..62"); \ static struct _ddebug_class_user __aligned(8) __used \ __section("__dyndbg_class_users") _uname =3D { \ .mod_name =3D KBUILD_MODNAME, \ diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 2083a8546460..635df6edb4cf 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -320,7 +320,7 @@ static bool ddebug_match_desc(const struct ddebug_query= *query, /* site is class'd */ site_map =3D ddebug_find_map_by_class_id(di, dp->class_id); if (!site_map) { - WARN_ONCE(1, "unknown class_id %d, check %s's CLASSMAP definitions", + pr_warn_ratelimited("unknown class_id %d, check %s's CLASSMAP definition= s\n", dp->class_id, di->mod_name); return false; } @@ -1404,9 +1404,8 @@ static void ddebug_apply_class_users(const struct _dd= ebug_info *di) (__dst)->info._vec.len =3D __nc; \ }) =20 -static int __maybe_unused -ddebug_class_range_overlap(struct _ddebug_class_map *cm, - u64 *reserved_ids) +static int ddebug_class_range_overlap(struct _ddebug_class_map *cm, + u64 *reserved_ids) { u64 range =3D (((1ULL << cm->length) - 1) << cm->base); =20 @@ -1420,6 +1419,23 @@ ddebug_class_range_overlap(struct _ddebug_class_map = *cm, return 0; } =20 +static int ddebug_class_user_overlap(struct _ddebug_class_user *cli, + u64 *reserved_ids) +{ + struct _ddebug_class_map *cm =3D cli->map; + int base =3D cm->base + cli->offset; + u64 range =3D (((1ULL << cm->length) - 1) << base); + + if (range & *reserved_ids) { + pr_err("[%d..%d] (from %s) conflicts with %llx\n", base, + base + cm->length - 1, cm->class_names[0], + *reserved_ids); + return -EINVAL; + } + *reserved_ids |=3D range; + return 0; +} + /* * Allocate a new ddebug_table for the given module * and add it to the global list. @@ -1430,6 +1446,7 @@ static int ddebug_add_module(struct _ddebug_info *di) struct _ddebug_class_map *cm; struct _ddebug_class_user *cli; u64 reserved_ids =3D 0; + u64 bad_ids =3D 0; int i; =20 if (!di->descs.len) @@ -1454,10 +1471,33 @@ static int ddebug_add_module(struct _ddebug_info *d= i) dd_mark_vector_subrange(i, cli, &dt->info, users, dt); /* now di is stale */ =20 - /* insure 2+ classmaps share the per-module 0..62 class_id space */ - for_subvec(i, cm, &dt->info, maps) + /* validate class map types and the per-module 0..62 class_id space */ + for_subvec(i, cm, &dt->info, maps) { + if (cm->map_type > DD_CLASS_TYPE_LEVEL_NUM) { + pr_err("module %s has unknown classmap type %d\n", dt->info.mod_name, c= m->map_type); + goto cleanup; + } if (ddebug_class_range_overlap(cm, &reserved_ids)) goto cleanup; + } + + for_subvec(i, cli, &dt->info, users) + if (ddebug_class_user_overlap(cli, &reserved_ids)) + goto cleanup; + + /* validate all class_ids against module's classmaps/users */ + for (i =3D 0; i < dt->info.descs.len; i++) { + struct _ddebug *dp =3D &dt->info.descs.start[i]; + + if (dp->class_id =3D=3D _DPRINTK_CLASS_DFLT) + continue; + if (bad_ids & (1ULL << dp->class_id)) + continue; + if (!ddebug_find_map_by_class_id(&dt->info, dp->class_id)) { + pr_warn("module %s uses unknown class_id %d\n", dt->info.mod_name, dp->= class_id); + bad_ids |=3D (1ULL << dp->class_id); + } + } =20 mutex_lock(&ddebug_lock); list_add_tail(&dt->link, &ddebug_tables); --=20 2.53.0