From: Jim Cromie <[email protected]> If a module _DEFINEs 2 or more classmaps, it must devise them to share the per-module 0..62 class-id space; ie their respective base,+length reservations cannot overlap.
To detect conflicts at modprobe, add ddebug_class_range_overlap(), call it from ddebug_add_module(), and WARN and return -EINVAL when they're detected. This insures that class_id -> classname lookup has just 1 answer, so the 1st-found search in find-class-name works properly. test_dynamic_debug.c: If built with -DFORCE_CLASSID_CONFLICT, the test-modules invoke 2 conflicting DYNAMIC_DEBUG_CLASSMAP_DEFINE() declarations, into parent and the _submod. These conflict with one of the good ones in the parent (D2_CORE..etc), causing the modprobe(s) to WARN and fail. Signed-off-by: Jim Cromie <[email protected]> Reviewed-by: Louis Chauvet <[email protected]> --- v2: RvB after SoB old-v9 - fix WARN() by adding new 1st arg 1. old-v12 - drop maybe_unused on range-overlap fn --- lib/dynamic_debug.c | 40 ++++++++++++++++++++++++++++++++-------- lib/test_dynamic_debug.c | 8 ++++++++ 2 files changed, 40 insertions(+), 8 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index ba618dcf9677..0f89b6784ab2 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -1101,18 +1101,19 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos) return dp; } -static bool ddebug_class_in_range(const int class_id, const struct ddebug_class_map *map) +static bool ddebug_class_map_in_range(const int class_id, const struct ddebug_class_map *map) { + if (!map) + return false; return (class_id >= map->base && class_id < map->base + map->length); } -static bool ddebug_user_class_in_range(const int class_id, const struct ddebug_class_user *cli) +static bool ddebug_class_user_in_range(const int class_id, const struct ddebug_class_user *user) { - if (!cli || !cli->map) + if (!user) return false; - int base = cli->map->base + cli->offset; - return (class_id >= base && class_id < base + cli->map->length); + return ddebug_class_map_in_range(class_id - user->offset, user->map); } static const char *ddebug_class_name(struct _ddebug_info *di, struct _ddebug *dp) @@ -1122,11 +1123,11 @@ static const char *ddebug_class_name(struct _ddebug_info *di, struct _ddebug *dp int i; for_subvec(i, map, di, maps) - if (ddebug_class_in_range(dp->class_id, map)) + if (ddebug_class_map_in_range(dp->class_id, map)) return map->class_names[dp->class_id - map->base]; for_subvec(i, cli, di, users) - if (ddebug_user_class_in_range(dp->class_id, cli)) + if (ddebug_class_user_in_range(dp->class_id, cli)) return cli->map->class_names[dp->class_id - cli->map->base - cli->offset]; return NULL; @@ -1369,6 +1370,20 @@ static void ddebug_apply_class_users(const struct _ddebug_info *di) __di->_vec.start = __start; \ }) +static int ddebug_class_range_overlap(struct ddebug_class_map *cm, u64 *reserved_ids) +{ + u64 range = (((1ULL << cm->length) - 1) << cm->base); + + if (range & *reserved_ids) { + pr_err("[%d..%d] on %s conflicts with %llx\n", cm->base, + cm->base + cm->length - 1, cm->class_names[0], + *reserved_ids); + return -EINVAL; + } + *reserved_ids |= range; + return 0; +} + /* * Allocate a new ddebug_table for the given module * and add it to the global list. @@ -1378,6 +1393,7 @@ static int ddebug_add_module(struct _ddebug_info *di) struct ddebug_table *dt; struct ddebug_class_map *cm; struct ddebug_class_user *cli; + u64 reserved_ids = 0; int i; if (!di->descs.len) @@ -1409,16 +1425,24 @@ static int ddebug_add_module(struct _ddebug_info *di) dd_set_module_subrange(i, cm, &dt->info, maps); dd_set_module_subrange(i, cli, &dt->info, users); + /* insure 2+ classmaps share the per-module 0..62 class_id space */ + for_subvec(i, cm, &dt->info, maps) + if (ddebug_class_range_overlap(cm, &reserved_ids)) + goto cleanup; + mutex_lock(&ddebug_lock); list_add_tail(&dt->link, &ddebug_tables); mutex_unlock(&ddebug_lock); - if (dt->info.users.len) ddebug_apply_class_users(&dt->info); vpr_info("%3u debug prints in module %s\n", dt->info.descs.len, dt->info.mod_name); return 0; +cleanup: + WARN_ONCE(1, "dyndbg multi-classmap conflict in %s\n", di->mod_name); + kfree(dt); + return -EINVAL; } /* helper for ddebug_dyndbg_(boot|module)_param_cb */ diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c index 34e51996aa20..3a69cc3cae6d 100644 --- a/lib/test_dynamic_debug.c +++ b/lib/test_dynamic_debug.c @@ -128,6 +128,14 @@ DYNAMIC_DEBUG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, DYNAMIC_DEBUG_CLASSMAP_DEFINE(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, V1, "V1", "V2", "V3", "V4", "V5", "V6", "V7"); +#ifdef FORCE_CLASSID_CONFLICT +/* + * Enable with -Dflag on compile to test overlapping class-id range + * detection. This should warn on modprobes. + */ +DYNAMIC_DEBUG_CLASSMAP_DEFINE(classid_range_conflict, 0, D2_CORE + 1, "D3_CORE"); +#endif + #else /* TEST_DYNAMIC_DEBUG_SUBMOD */ /* -- 2.55.0
