| Message ID | 20240429193145.66543-1-jim.cromie@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | fix CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression | expand |
On Mon, Apr 29, 2024 at 1:32 PM Jim Cromie <jim.cromie@gmail.com> wrote: > > hi Greg, Jason, DRM-folk, > > This patchset fixes the CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression, > Fixes: bb2ff6c27bc9 ("drm: Disable dynamic debug as broken") > > this is v8. > Its also here: > https://github.com/jimc/linux/tree/dd-classmap-fix-8a > This patchset didnt get picked up by drm patchwork maybe its tired my stochastic renaming, sorry about that https://patchwork.freedesktop.org/project/intel-gfx/series/?ordering=-last_updated 125063fix DRM_USE_DYNAMIC_DEBUG=y regressionwarningNew23jim.cromie@gmail.comNone2023-11-01 123572fix DRM_USE_DYNAMIC_DEBUG regressionfailureNew22jim.cromie@gmail.comNone2023-09-11 113363fix DRM_USE_DYNAMIC_DEBUG regressionwarningIn progress 22jim.cromie@gmail.comNone2023-08-01 111651DRM_USE_DYNAMIC_DEBUG regressionfailureNew20jim.cromie@gmail.comNone2023-01-13 111631DRM - avoid regression in -rc, fix comment is there something missing for a DRM patchwork run ? does it kick out because theres non-drm subsystem stuff in there ? thanks > v7 had at least 2 problems: > > https://lore.kernel.org/lkml/20231101002609.3533731-1-jim.cromie@gmail.com/ > https://patchwork.freedesktop.org/series/125066/ > > 1. missing __align(8) in METATDATA macro, giving too much placement > freedom to linker, caused weird segvs following non-ptr vals, but for > builtin modules only. found by lkp-test. > > 2. the main patch changed both the dyndbg API, and the drm/drivers. > This was a flag-day annoyance, and not practical. Fix by preserving > old API macro until "later", and splitting the patch and set into 2 > sequential subsets. removal can wait. > > What was broken ? > > Booting a modular kernel with drm.debug=0x1ff, this enabled pr_debugs > only in drm itself, not the yet-to-be loaded driver + helpers. I had > tested with scripts doing lots of modprobes with dyndbg=<> options > permuting. I didn't notice that I didn't really test without them. > > The deeper cause was my design error, a violation of the K&R rule: > "define once, refer many times". > > DECLARE_DYNDBG_CLASSMAP defined the classmap, and was used everywhere, > re-declaring the same static classmap repeatedly. Jani Nikula actually > picked up on this at the time, but didn't scream loudly enough for > anyone to notice, I know I didn't get it then. One patchset across 2 > trees didn't help either. > > The revised classmap API "splits" it to def & ref. > > DYNDBG_CLASSMAP_DEFINE fixes & updates the busted macro, EXPORTing the > classmap instead. It gets invoked once per subsystem, by the > parent/builtin, drm.ko for DRM. > > DYNDBG_CLASSMAP_USE in drivers and helpers refer to the classmap by > name, which links the 2 modules (like __drm_debug already does). > > These 2 tell dyndbg to map "class FOO" to the defined FOO_ID, which > allows it to make those changes via >control. > > DYNDBG_CLASSMAP_PARAM*, defines the controlling kparam, and binds it > to both the _var, and the _DEFINEd classmap. So drm uses this to bind > the classmap to __drm_debug. > > It provides the common control-point for the sub-system; it is applied > to the classmaps during modprobe of both _DEFINEr and USErs. It also > enforces the relative nature of LEVEL classmaps, ie V3>V2. > > DECLARE_DYNDBG_CLASSMAP is preserved to decouple the DRM patches. > > A new struct and elf section contain the _USEs; on modprobe, these are > scanned similarly to the _DEFINEs, but follow the references to their > defining modules, find the kparam wired to the classmap, and apply its > classmap settings to the USEr. This action is what V1 missed, which > is why drivers failed to enable debug during modprobe. > > In order to recapitulate the regression scenario without involving > DRM, the patchset (v6 I think) adds test_dynamic_debug_submod, which > is a duplicate of its parent; _submod.c #defines _SUBMOD, and then > includes parent. > > This puts _DEFINE and _USE close together in the same file, for > obviousness. It also guarantees that the submod always has the same > complement of debug()s, giving consistent output from both when > classmaps are working properly, as tested when changing callsites via > both param and >control. > > To provide a turn-key selftest, the patchset also adds > ./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh, pilfered > from a debug-to-trace patchset I and Lukasz Bartozik have been working > out. It starts with basic_tests, then to test 2 new parsing > delimiters, which simplify testing of the classmap functionality. > > It works nicely from virtme-ng: > > [jimc@frodo vx]$ vrun_ -- ./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh > doing: vng --verbose --name v6.9-rc5-34-g2f1ace6e1c68 \ > --user root --cwd ../.. \ > -a dynamic_debug.verbose=2 -p 4 \ > -- ./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh > virtme: waiting for virtiofsd to start > ... > [ 3.546739] ip (260) used greatest stack depth: 12368 bytes left > [ 3.609288] virtme-init: starting script > test_dynamic_debug_submod not there > test_dynamic_debug not there > # BASIC_TESTS > ... > # Done on: Fri Apr 26 20:45:08 MDT 2024 > [ 4.765751] virtme-init: script returned {0} > Powering off. > [ 4.805790] ACPI: PM: Preparing to enter system sleep state S5 > [ 4.806223] kvm: exiting hardware virtualization > [ 4.806564] reboot: Power down > [jimc@frodo vx]$ > > > I've been running the kernel on my x86 desktop & laptop, booting with > drm.debug=0x1f, then turning it all-off after sleep 15. > > a few highlights from a bare-metal boot: > > here modprobe amdgpu; dyndbg applies last bit/class/category, and finishes init, > then drm and amdgpu start logging as they execute > ... > [ 9.019696] gandalf kernel: dyndbg: query 0: "class DRM_UT_ATOMIC +p" mod:amdgpu > [ 9.019704] gandalf kernel: dyndbg: class-ref: amdgpu.DRM_UT_ATOMIC module:amdgpu nd:4754 nc:0 nu:1 > [ 9.020012] gandalf kernel: dyndbg: processed 1 queries, with 21 matches, 0 errs > [ 9.020017] gandalf kernel: dyndbg: bit_4: 21 matches on class: DRM_UT_ATOMIC -> 0x1f > [ 9.020021] gandalf kernel: dyndbg: applied bitmap: 0x1f to: 0x0 for amdgpu > [ 9.020026] gandalf kernel: dyndbg: attach-client-module: module:amdgpu nd:4754 nc:0 nu:1 > [ 9.020031] gandalf kernel: dyndbg: 4754 debug prints in module amdgpu > [ 9.055065] gandalf kernel: [drm] amdgpu kernel modesetting enabled. > [ 9.055138] gandalf kernel: [drm:amdgpu_acpi_detect [amdgpu]] No matching acpi device found for AMD3000 > [ 9.055564] gandalf kernel: amdgpu: Virtual CRAT table created for CPU > [ 9.055585] gandalf kernel: amdgpu: Topology: Add CPU node > [ 9.055752] gandalf kernel: amdgpu 0000:0c:00.0: enabling device (0006 -> 0007) > [ 9.055821] gandalf kernel: [drm] initializing kernel modesetting (NAVI10 0x1002:0x731F 0x148C:0x2398 0xC1). > [ 9.055835] gandalf kernel: [drm] register mmio base: 0xFCB00000 > [ 9.055839] gandalf kernel: [drm] register mmio size: 524288 > [ 9.059148] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] number of dies: 1 > [ 9.059387] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] number of hardware IPs on die0: 39 > [ 9.059623] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] ATHUB(35) #0 v2.0.0: > [ 9.059856] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] 0x00000c00 > [ 9.060096] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] 0x02408c00 > [ 9.060328] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] set register base offset for ATHUB > > a startup script, after sleep 15, turns off the logging: > > echo 0 > /sys/module/drm/parameters/debug > > heres 1st 2 bits/classes/categories being turned off: > > [ 29.105991] gandalf kernel: [drm:amdgpu_ih_process [amdgpu]] amdgpu_ih_process: rptr 90752, wptr 90784 > [ 29.118086] gandalf kernel: dyndbg: bits:0x0 > *.debug > [ 29.118096] gandalf kernel: dyndbg: apply bitmap: 0x0 to: 0x1f for '*' > [ 29.118102] gandalf kernel: dyndbg: query 0: "class DRM_UT_CORE -p" mod:* > [ 29.118122] gandalf kernel: dyndbg: good-class: drm.DRM_UT_CORE module:drm nd:338 nc:1 nu:0 > [ 29.119548] gandalf kernel: dyndbg: class-ref: drm_kms_helper.DRM_UT_CORE module:drm_kms_helper nd:93 > nc:0 nu:1 > [ 29.119552] gandalf kernel: dyndbg: class-ref: drm_display_helper.DRM_UT_CORE module:drm_display_helper nd:151 nc:0 nu:1 > [ 29.119737] gandalf kernel: dyndbg: class-ref: amdgpu.DRM_UT_CORE module:amdgpu nd:4754 nc:0 nu:1 > [ 29.122181] gandalf kernel: [drm:amdgpu_ih_process [amdgpu]] amdgpu_ih_process: rptr 90784, wptr 90816 > [ 29.127687] gandalf kernel: dyndbg: processed 1 queries, with 466 matches, 0 errs > [ 29.127690] gandalf kernel: dyndbg: bit_0: 466 matches on class: DRM_UT_CORE -> 0x0 > [ 29.127692] gandalf kernel: dyndbg: query 0: "class DRM_UT_DRIVER -p" mod:* > [ 29.127696] gandalf kernel: dyndbg: good-class: drm.DRM_UT_DRIVER module:drm nd:338 nc:1 nu:0 > [ 29.127699] gandalf kernel: dyndbg: class-ref: drm_kms_helper.DRM_UT_DRIVER module:drm_kms_helper nd:93 nc:0 nu:1 > [ 29.127701] gandalf kernel: dyndbg: class-ref: drm_display_helper.DRM_UT_DRIVER module:drm_display_helper nd:151 nc:0 nu:1 > [ 29.127885] gandalf kernel: dyndbg: class-ref: amdgpu.DRM_UT_DRIVER module:amdgpu nd:4754 nc:0 nu:1 > [ 29.152925] gandalf kernel: dyndbg: processed 1 queries, with 1384 matches, 0 errs > > > The resulting journal is ~14.6k lines, written in the 1st 15 (29) > seconds of startup. I'm unsure what the 15/29 discrepancy might > indicate/betray, besides a lot of logging work. sleep 15 is not the > best stopwatch. > > recent spins thru lkp-test have also been SUCCESS-ful. > > Jim Cromie (35): > > old-bugs & cleanups: > dyndbg: fix old BUG_ON in >control parser > docs/dyndbg: update examples \012 to \n > test-dyndbg: fixup CLASSMAP usage error > dyndbg: reword "class unknown," to "class:_UNKNOWN_" > dyndbg: make ddebug_class_param union members same size > dyndbg: replace classmap list with a vector > dyndbg: ddebug_apply_class_bitmap - add module arg, select on it > dyndbg: split param_set_dyndbg_classes to _module & wrapper fns > dyndbg: drop NUM_TYPE_ARRAY > dyndbg: reduce verbose/debug clutter > dyndbg: silence debugs with no-change updates > dyndbg: tighten ddebug_class_name() 1st arg type > dyndbg: tighten fn-sig of ddebug_apply_class_bitmap > dyndbg: reduce verbose=3 messages in ddebug_add_module > dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code > > core fix & selftests: > dyndbg-API: fix DECLARE_DYNDBG_CLASSMAP > selftests-dyndbg: add tools/testing/selftests/dynamic_debug/* > selftests-dyndbg: exit 127 if no facility > dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API > dyndbg-doc: add classmap info to howto > dyndbg: treat comma as a token separator > selftests-dyndbg: add comma_terminator_tests > dyndbg: split multi-query strings with % > selftests-dyndbg: test_percent_splitting multi-cmds on module classes > docs/dyndbg: explain new delimiters: comma, percent > selftests-dyndbg: add test_mod_submod > selftests-dyndbg: test dyndbg-to-tracefs > dyndbg-doc: explain flags parse 1st > dyndbg: add __counted_by annotations > > DRM parts > drm+drivers: adapt to use DYNDBG_CLASSMAP_{DEFINE,USE} > drm-dyndbg: adapt to use DYNDBG_CLASSMAP_PARAM > drm: use correct ccflags-y spelling > drm-drivers: DRM_CLASSMAP_USE in 2nd batch of drivers, helpers > drm: restore CONFIG_DRM_USE_DYNAMIC_DEBUG un-BROKEN > drm-print: workaround compiler meh > > .../admin-guide/dynamic-debug-howto.rst | 99 ++- > MAINTAINERS | 3 +- > drivers/gpu/drm/Kconfig | 3 +- > drivers/gpu/drm/Makefile | 3 +- > drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 12 +- > drivers/gpu/drm/display/drm_dp_helper.c | 12 +- > drivers/gpu/drm/drm_crtc_helper.c | 12 +- > drivers/gpu/drm/drm_gem_shmem_helper.c | 2 + > drivers/gpu/drm/drm_print.c | 38 +- > drivers/gpu/drm/gud/gud_drv.c | 2 + > drivers/gpu/drm/i915/i915_params.c | 12 +- > drivers/gpu/drm/mgag200/mgag200_drv.c | 2 + > drivers/gpu/drm/nouveau/nouveau_drm.c | 12 +- > drivers/gpu/drm/qxl/qxl_drv.c | 2 + > drivers/gpu/drm/radeon/radeon_drv.c | 2 + > drivers/gpu/drm/udl/udl_main.c | 2 + > drivers/gpu/drm/vkms/vkms_drv.c | 2 + > drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 2 + > include/asm-generic/vmlinux.lds.h | 1 + > include/drm/drm_print.h | 10 + > include/linux/dynamic_debug.h | 130 ++- > kernel/module/main.c | 3 + > lib/Kconfig.debug | 24 +- > lib/Makefile | 3 + > lib/dynamic_debug.c | 443 ++++++---- > lib/test_dynamic_debug.c | 131 +-- > lib/test_dynamic_debug_submod.c | 17 + > tools/testing/selftests/Makefile | 1 + > .../testing/selftests/dynamic_debug/Makefile | 9 + > tools/testing/selftests/dynamic_debug/config | 2 + > .../dynamic_debug/dyndbg_selftest.sh | 765 ++++++++++++++++++ > 31 files changed, 1398 insertions(+), 363 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 > > -- > 2.44.0 >
hi Greg, Jason, DRM-folk, This patchset fixes the CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression, Fixes: bb2ff6c27bc9 ("drm: Disable dynamic debug as broken") this is v8. Its also here: https://github.com/jimc/linux/tree/dd-classmap-fix-8a v7 had at least 2 problems: https://lore.kernel.org/lkml/20231101002609.3533731-1-jim.cromie@gmail.com/ https://patchwork.freedesktop.org/series/125066/ 1. missing __align(8) in METATDATA macro, giving too much placement freedom to linker, caused weird segvs following non-ptr vals, but for builtin modules only. found by lkp-test. 2. the main patch changed both the dyndbg API, and the drm/drivers. This was a flag-day annoyance, and not practical. Fix by preserving old API macro until "later", and splitting the patch and set into 2 sequential subsets. removal can wait. What was broken ? Booting a modular kernel with drm.debug=0x1ff, this enabled pr_debugs only in drm itself, not the yet-to-be loaded driver + helpers. I had tested with scripts doing lots of modprobes with dyndbg=<> options permuting. I didn't notice that I didn't really test without them. The deeper cause was my design error, a violation of the K&R rule: "define once, refer many times". DECLARE_DYNDBG_CLASSMAP defined the classmap, and was used everywhere, re-declaring the same static classmap repeatedly. Jani Nikula actually picked up on this at the time, but didn't scream loudly enough for anyone to notice, I know I didn't get it then. One patchset across 2 trees didn't help either. The revised classmap API "splits" it to def & ref. DYNDBG_CLASSMAP_DEFINE fixes & updates the busted macro, EXPORTing the classmap instead. It gets invoked once per subsystem, by the parent/builtin, drm.ko for DRM. DYNDBG_CLASSMAP_USE in drivers and helpers refer to the classmap by name, which links the 2 modules (like __drm_debug already does). These 2 tell dyndbg to map "class FOO" to the defined FOO_ID, which allows it to make those changes via >control. DYNDBG_CLASSMAP_PARAM*, defines the controlling kparam, and binds it to both the _var, and the _DEFINEd classmap. So drm uses this to bind the classmap to __drm_debug. It provides the common control-point for the sub-system; it is applied to the classmaps during modprobe of both _DEFINEr and USErs. It also enforces the relative nature of LEVEL classmaps, ie V3>V2. DECLARE_DYNDBG_CLASSMAP is preserved to decouple the DRM patches. A new struct and elf section contain the _USEs; on modprobe, these are scanned similarly to the _DEFINEs, but follow the references to their defining modules, find the kparam wired to the classmap, and apply its classmap settings to the USEr. This action is what V1 missed, which is why drivers failed to enable debug during modprobe. In order to recapitulate the regression scenario without involving DRM, the patchset (v6 I think) adds test_dynamic_debug_submod, which is a duplicate of its parent; _submod.c #defines _SUBMOD, and then includes parent. This puts _DEFINE and _USE close together in the same file, for obviousness. It also guarantees that the submod always has the same complement of debug()s, giving consistent output from both when classmaps are working properly, as tested when changing callsites via both param and >control. To provide a turn-key selftest, the patchset also adds ./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh, pilfered from a debug-to-trace patchset I and Lukasz Bartozik have been working out. It starts with basic_tests, then to test 2 new parsing delimiters, which simplify testing of the classmap functionality. It works nicely from virtme-ng: [jimc@frodo vx]$ vrun_ -- ./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh doing: vng --verbose --name v6.9-rc5-34-g2f1ace6e1c68 \ --user root --cwd ../.. \ -a dynamic_debug.verbose=2 -p 4 \ -- ./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh virtme: waiting for virtiofsd to start ... [ 3.546739] ip (260) used greatest stack depth: 12368 bytes left [ 3.609288] virtme-init: starting script test_dynamic_debug_submod not there test_dynamic_debug not there # BASIC_TESTS ... # Done on: Fri Apr 26 20:45:08 MDT 2024 [ 4.765751] virtme-init: script returned {0} Powering off. [ 4.805790] ACPI: PM: Preparing to enter system sleep state S5 [ 4.806223] kvm: exiting hardware virtualization [ 4.806564] reboot: Power down [jimc@frodo vx]$ I've been running the kernel on my x86 desktop & laptop, booting with drm.debug=0x1f, then turning it all-off after sleep 15. a few highlights from a bare-metal boot: here modprobe amdgpu; dyndbg applies last bit/class/category, and finishes init, then drm and amdgpu start logging as they execute ... [ 9.019696] gandalf kernel: dyndbg: query 0: "class DRM_UT_ATOMIC +p" mod:amdgpu [ 9.019704] gandalf kernel: dyndbg: class-ref: amdgpu.DRM_UT_ATOMIC module:amdgpu nd:4754 nc:0 nu:1 [ 9.020012] gandalf kernel: dyndbg: processed 1 queries, with 21 matches, 0 errs [ 9.020017] gandalf kernel: dyndbg: bit_4: 21 matches on class: DRM_UT_ATOMIC -> 0x1f [ 9.020021] gandalf kernel: dyndbg: applied bitmap: 0x1f to: 0x0 for amdgpu [ 9.020026] gandalf kernel: dyndbg: attach-client-module: module:amdgpu nd:4754 nc:0 nu:1 [ 9.020031] gandalf kernel: dyndbg: 4754 debug prints in module amdgpu [ 9.055065] gandalf kernel: [drm] amdgpu kernel modesetting enabled. [ 9.055138] gandalf kernel: [drm:amdgpu_acpi_detect [amdgpu]] No matching acpi device found for AMD3000 [ 9.055564] gandalf kernel: amdgpu: Virtual CRAT table created for CPU [ 9.055585] gandalf kernel: amdgpu: Topology: Add CPU node [ 9.055752] gandalf kernel: amdgpu 0000:0c:00.0: enabling device (0006 -> 0007) [ 9.055821] gandalf kernel: [drm] initializing kernel modesetting (NAVI10 0x1002:0x731F 0x148C:0x2398 0xC1). [ 9.055835] gandalf kernel: [drm] register mmio base: 0xFCB00000 [ 9.055839] gandalf kernel: [drm] register mmio size: 524288 [ 9.059148] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] number of dies: 1 [ 9.059387] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] number of hardware IPs on die0: 39 [ 9.059623] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] ATHUB(35) #0 v2.0.0: [ 9.059856] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] 0x00000c00 [ 9.060096] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] 0x02408c00 [ 9.060328] gandalf kernel: [drm:amdgpu_discovery_set_ip_blocks [amdgpu]] set register base offset for ATHUB a startup script, after sleep 15, turns off the logging: echo 0 > /sys/module/drm/parameters/debug heres 1st 2 bits/classes/categories being turned off: [ 29.105991] gandalf kernel: [drm:amdgpu_ih_process [amdgpu]] amdgpu_ih_process: rptr 90752, wptr 90784 [ 29.118086] gandalf kernel: dyndbg: bits:0x0 > *.debug [ 29.118096] gandalf kernel: dyndbg: apply bitmap: 0x0 to: 0x1f for '*' [ 29.118102] gandalf kernel: dyndbg: query 0: "class DRM_UT_CORE -p" mod:* [ 29.118122] gandalf kernel: dyndbg: good-class: drm.DRM_UT_CORE module:drm nd:338 nc:1 nu:0 [ 29.119548] gandalf kernel: dyndbg: class-ref: drm_kms_helper.DRM_UT_CORE module:drm_kms_helper nd:93 nc:0 nu:1 [ 29.119552] gandalf kernel: dyndbg: class-ref: drm_display_helper.DRM_UT_CORE module:drm_display_helper nd:151 nc:0 nu:1 [ 29.119737] gandalf kernel: dyndbg: class-ref: amdgpu.DRM_UT_CORE module:amdgpu nd:4754 nc:0 nu:1 [ 29.122181] gandalf kernel: [drm:amdgpu_ih_process [amdgpu]] amdgpu_ih_process: rptr 90784, wptr 90816 [ 29.127687] gandalf kernel: dyndbg: processed 1 queries, with 466 matches, 0 errs [ 29.127690] gandalf kernel: dyndbg: bit_0: 466 matches on class: DRM_UT_CORE -> 0x0 [ 29.127692] gandalf kernel: dyndbg: query 0: "class DRM_UT_DRIVER -p" mod:* [ 29.127696] gandalf kernel: dyndbg: good-class: drm.DRM_UT_DRIVER module:drm nd:338 nc:1 nu:0 [ 29.127699] gandalf kernel: dyndbg: class-ref: drm_kms_helper.DRM_UT_DRIVER module:drm_kms_helper nd:93 nc:0 nu:1 [ 29.127701] gandalf kernel: dyndbg: class-ref: drm_display_helper.DRM_UT_DRIVER module:drm_display_helper nd:151 nc:0 nu:1 [ 29.127885] gandalf kernel: dyndbg: class-ref: amdgpu.DRM_UT_DRIVER module:amdgpu nd:4754 nc:0 nu:1 [ 29.152925] gandalf kernel: dyndbg: processed 1 queries, with 1384 matches, 0 errs The resulting journal is ~14.6k lines, written in the 1st 15 (29) seconds of startup. I'm unsure what the 15/29 discrepancy might indicate/betray, besides a lot of logging work. sleep 15 is not the best stopwatch. recent spins thru lkp-test have also been SUCCESS-ful. Jim Cromie (35): old-bugs & cleanups: dyndbg: fix old BUG_ON in >control parser docs/dyndbg: update examples \012 to \n test-dyndbg: fixup CLASSMAP usage error dyndbg: reword "class unknown," to "class:_UNKNOWN_" dyndbg: make ddebug_class_param union members same size dyndbg: replace classmap list with a vector dyndbg: ddebug_apply_class_bitmap - add module arg, select on it dyndbg: split param_set_dyndbg_classes to _module & wrapper fns dyndbg: drop NUM_TYPE_ARRAY dyndbg: reduce verbose/debug clutter dyndbg: silence debugs with no-change updates dyndbg: tighten ddebug_class_name() 1st arg type dyndbg: tighten fn-sig of ddebug_apply_class_bitmap dyndbg: reduce verbose=3 messages in ddebug_add_module dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code core fix & selftests: dyndbg-API: fix DECLARE_DYNDBG_CLASSMAP selftests-dyndbg: add tools/testing/selftests/dynamic_debug/* selftests-dyndbg: exit 127 if no facility dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API dyndbg-doc: add classmap info to howto dyndbg: treat comma as a token separator selftests-dyndbg: add comma_terminator_tests dyndbg: split multi-query strings with % selftests-dyndbg: test_percent_splitting multi-cmds on module classes docs/dyndbg: explain new delimiters: comma, percent selftests-dyndbg: add test_mod_submod selftests-dyndbg: test dyndbg-to-tracefs dyndbg-doc: explain flags parse 1st dyndbg: add __counted_by annotations DRM parts drm+drivers: adapt to use DYNDBG_CLASSMAP_{DEFINE,USE} drm-dyndbg: adapt to use DYNDBG_CLASSMAP_PARAM drm: use correct ccflags-y spelling drm-drivers: DRM_CLASSMAP_USE in 2nd batch of drivers, helpers drm: restore CONFIG_DRM_USE_DYNAMIC_DEBUG un-BROKEN drm-print: workaround compiler meh .../admin-guide/dynamic-debug-howto.rst | 99 ++- MAINTAINERS | 3 +- drivers/gpu/drm/Kconfig | 3 +- drivers/gpu/drm/Makefile | 3 +- drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 12 +- drivers/gpu/drm/display/drm_dp_helper.c | 12 +- drivers/gpu/drm/drm_crtc_helper.c | 12 +- drivers/gpu/drm/drm_gem_shmem_helper.c | 2 + drivers/gpu/drm/drm_print.c | 38 +- drivers/gpu/drm/gud/gud_drv.c | 2 + drivers/gpu/drm/i915/i915_params.c | 12 +- drivers/gpu/drm/mgag200/mgag200_drv.c | 2 + drivers/gpu/drm/nouveau/nouveau_drm.c | 12 +- drivers/gpu/drm/qxl/qxl_drv.c | 2 + drivers/gpu/drm/radeon/radeon_drv.c | 2 + drivers/gpu/drm/udl/udl_main.c | 2 + drivers/gpu/drm/vkms/vkms_drv.c | 2 + drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 2 + include/asm-generic/vmlinux.lds.h | 1 + include/drm/drm_print.h | 10 + include/linux/dynamic_debug.h | 130 ++- kernel/module/main.c | 3 + lib/Kconfig.debug | 24 +- lib/Makefile | 3 + lib/dynamic_debug.c | 443 ++++++---- lib/test_dynamic_debug.c | 131 +-- lib/test_dynamic_debug_submod.c | 17 + tools/testing/selftests/Makefile | 1 + .../testing/selftests/dynamic_debug/Makefile | 9 + tools/testing/selftests/dynamic_debug/config | 2 + .../dynamic_debug/dyndbg_selftest.sh | 765 ++++++++++++++++++ 31 files changed, 1398 insertions(+), 363 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