CONFIG_DRM_USE_DYNAMIC_DEBUG=y has a regression; drm subsystem modules, which depend upon drm.ko and use the drm.debug API, do not get enabled when __drm_debug is set by `modprobe drm debug=0x1f`. With =N, __drm_debug is checked before logging the msg, so the end-of-modprobe debug=$init affected all later checks. But with =y, each run-time check is replaced by a static-key that is set at end-of-modprobe. This creates a chicken-egg dependency; i915 must be modprobed before its drm.debugs are enabled, but drm.ko (and __drm_debug=$init) must be done before modprobe i915, so its callsites arent there yet to be enabled. The fix is to split DECLARE_DYNDBG_CLASSMAP to: DYNDBG_CLASSMAP_DEFINE - invoked in 'parent' DYNDBG_CLASSMAP_USE - invoked in dependent, to USE the exported definition To prove the fix w/o involving DRM, we need 2 modules, one dependent on the other. Add test_dynamic_debug_submod.ko, which _USEs the classmaps _exported by test_dynamic_debug.ko To keep code to a minimum, test_dynamic_debug.c ifdefs on TEST_DYNAMIC_DEBUG_SUBMOD to build either parent or dependent, with either DYNDBG_CLASSMAP_DEFINE or DYNDBG_CLASSMAP_USE invocations. So test_dynamic_debug_submod.c is just 2 lines: include the .c after defining SUBMOD. This also gives the 2 modules identical prdbg callsites, only differing by enablement/configuration. Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx> --- lib/Makefile | 3 +- lib/test_dynamic_debug.c | 52 ++++++++++++++++++++++++++++----- lib/test_dynamic_debug_submod.c | 10 +++++++ 3 files changed, 57 insertions(+), 8 deletions(-) create mode 100644 lib/test_dynamic_debug_submod.c diff --git a/lib/Makefile b/lib/Makefile index 4d9461bfea42..7f7e75f44cd7 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -77,7 +77,7 @@ obj-$(CONFIG_TEST_SORT) += test_sort.o obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o -obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o +obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o test_dynamic_debug_submod.o obj-$(CONFIG_TEST_PRINTF) += test_printf.o obj-$(CONFIG_TEST_SCANF) += test_scanf.o obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o @@ -98,6 +98,7 @@ obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE) obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o + # # CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns # off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c index e678884066bf..8c005c17f2db 100644 --- a/lib/test_dynamic_debug.c +++ b/lib/test_dynamic_debug.c @@ -6,7 +6,11 @@ * Jim Cromie <jim.cromie@xxxxxxxxx> */ -#define pr_fmt(fmt) "test_dd: " fmt +#if defined(TEST_DYNAMIC_DEBUG_SUBMOD) + #define pr_fmt(fmt) "test_dd_submod: " fmt +#else + #define pr_fmt(fmt) "test_dd: " fmt +#endif #define DEBUG /* enable all prdbgs (plain & class'd) at compiletime */ @@ -49,6 +53,14 @@ module_param_cb(do_prints, ¶m_ops_do_prints, NULL, 0600); }; \ module_param_cb(_flags##_##_model, ¶m_ops_dyndbg_classes, &_flags##_model, 0600) +/* + * dynamic-debug imitates drm.debug's use of enums (DRM_UT_CORE etc) + * to define its classes/categories. dyndbg allows class-id's 0..62, + * reserving 63 for plain old (non-class'd) prdbgs. A module can + * define multiple classmaps, as long as they claim non-overlapping + * subranges. + */ + /* numeric input, independent bits */ enum cat_disjoint_bits { D2_CORE = 0, @@ -61,7 +73,36 @@ enum cat_disjoint_bits { D2_LEASE, D2_DP, D2_DRMRES }; + +/* symbolic input, independent bits */ +enum cat_disjoint_names { LOW = 10, MID, HI }; + +/* numeric verbosity, V2 > V1 related */ +enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 }; + +/* symbolic verbosity */ +enum cat_level_names { L0 = 22, L1, L2, L3, L4, L5, L6, L7 }; + +#if defined(TEST_DYNAMIC_DEBUG_SUBMOD) + +/* use the classmaps defined in 'parent' module below */ +DYNDBG_CLASSMAP_USE(map_disjoint_bits); +DYNDBG_CLASSMAP_USE(map_disjoint_names); +DYNDBG_CLASSMAP_USE(map_level_num); +DYNDBG_CLASSMAP_USE(map_level_names); + +#else + +/* + * parent module, define a classmap of each of 4 types. + * enum values are class-ids + * enum symbols are stringified, used as classnames + * param bits are mapped in order: 0..N + * (a straight, obvious, linear map is encouraged) + */ + DYNDBG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, + /* bits 0..N of param are mapped to these class-ids */ D2_CORE, D2_DRIVER, D2_KMS, @@ -75,27 +116,23 @@ DYNDBG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, DD_SYS_WRAP(disjoint_bits, p); DD_SYS_WRAP(disjoint_bits, T); -/* symbolic input, independent bits */ -enum cat_disjoint_names { LOW = 10, MID, HI }; DYNDBG_CLASSMAP_DEFINE(map_disjoint_names, DD_CLASS_TYPE_DISJOINT_NAMES, LOW, MID, HI); DD_SYS_WRAP(disjoint_names, p); DD_SYS_WRAP(disjoint_names, T); -/* numeric verbosity, V2 > V1 related */ -enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 }; DYNDBG_CLASSMAP_DEFINE(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, V0, V1, V2, V3, V4, V5, V6, V7); DD_SYS_WRAP(level_num, p); DD_SYS_WRAP(level_num, T); -/* symbolic verbosity */ -enum cat_level_names { L0 = 22, L1, L2, L3, L4, L5, L6, L7 }; DYNDBG_CLASSMAP_DEFINE(map_level_names, DD_CLASS_TYPE_LEVEL_NAMES, L0, L1, L2, L3, L4, L5, L6, L7); DD_SYS_WRAP(level_names, p); DD_SYS_WRAP(level_names, T); +#endif /* TEST_DYNAMIC_DEBUG_SUBMOD */ + /* stand-in for all pr_debug etc */ #define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n") @@ -142,6 +179,7 @@ static void do_levels(void) static void do_prints(void) { + pr_debug("do_prints:\n"); do_cats(); do_levels(); } diff --git a/lib/test_dynamic_debug_submod.c b/lib/test_dynamic_debug_submod.c new file mode 100644 index 000000000000..9a893402ce1a --- /dev/null +++ b/lib/test_dynamic_debug_submod.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Kernel module for testing dynamic_debug + * + * Authors: + * Jim Cromie <jim.cromie@xxxxxxxxx> + */ + +#define TEST_DYNAMIC_DEBUG_SUBMOD +#include "test_dynamic_debug.c" -- 2.39.1