[PATCH v6 00/22] fix DRM_USE_DYNAMIC_DEBUG regression
Jim Cromie
jim.cromie at gmail.com
Mon Sep 11 23:07:55 UTC 2023
This series fixes the regression in DRM_USE_DYNAMIC_DEBUG=y
blame analysis: (all mine)
1. my early test scripts did a lot of 'modprobe $m $*',
with dyndbg=.. and debug=.. args
this obscured the lack of drm.debug -> drivers propagation
2. I broke K&R rule: "define once, refer many times".
the classmaps DECLAREd by the drivers would run on args in 1
The thinko beneath that was imitating the "static struct" in the
definition of DEFINE_DYNAMIC_DEBUG_METADATA. Imitating __drm_debug
export instead broke the mental logjam.
So the patchset splits DECLARE_DYNDBG_CLASSMAP duty in 2: with
DYNDBG_CLASSMAP_DEFINE/_USE, where _DEFINE exports the classmap, so
_USE can reference it. The _USEs are added into a new section:
__dyndbg_class_users.
ddebug_add_module() now also scans class_users at modprobe time,
whence it finds the kernel-param that refs the classmap, and applies
its initialized state to the user/driver.
test-dynamic-debug is extended with a _submod, allowing it to
recapitulate the drm.ddebug -/-> drivers failure scenario.
NOTE: patch-14 does the DECLARE -> _DEFINE/_USE, so it also changes
DRM to follow the API change. That makes it buildable, but crosses 2
trees, which isn't so great. But since the feature is marked BROKEN
at this point, perhaps I should have split them.
Finally 3 DRM patches: drops BROKEN on DRM_USE_DYNAMIC_DEBUG, fixes
drm/Makefile, and wires a bunch more drivers to _USE DRM's
drm_debug_classmap.
You can bang at the test module with:
#!/bin/bash
ddcmd () {
echo $* > /proc/dynamic_debug/control
}
vx () {
echo $1 > /sys/module/dynamic_debug/parameters/verbose
}
ddgrep () {
grep $1 /proc/dynamic_debug/control
}
doprints () {
cat /sys/module/test_dynamic_debug/parameters/do_prints
}
note () {
echo NOTE: $* >&2
$*
}
ddparms () {
note ls -l /sys/module/test_dynamic_debug/parameters/
note cat /sys/module/test_dynamic_debug/parameters/*
}
up () {
modprobe drm debug=0x03 debug_trace=0x1ff
}
dn () {
rmmod drm
}
ddtraceon () {
echo 1 > /sys/kernel/tracing/tracing_on
echo 1 > /sys/kernel/tracing/events/dyndbg/enable
}
# replay drm.debug dependent-module scenario
submod () {
echo MP test_dynamic_debug $1 $2 dyndbg=+pm $3 $4
# extra complexity to avoid passing param=s since theyre explicit inits
if [[ -z $1 ]] ; then
modprobe test_dynamic_debug dyndbg=+pm
elif [[ -z $2 ]] ; then
modprobe test_dynamic_debug dyndbg=+pm \
p_disjoint_bits=${1:-0}
elif [[ -z $3 ]] ; then
# force 3,4 off, undoing DEBUG - declutter
modprobe test_dynamic_debug dyndbg=+pm \
p_disjoint_bits=${1:-0} p_level_num=${2:-0}
# p_disjoint_names=${3:-MID,-LOW,-HI} p_level_names=${4:-L3}
elif [[ -z $4 ]] ; then
modprobe test_dynamic_debug dyndbg=+pm \
p_disjoint_bits=${1:-0} p_level_num=${2:-0}
# p_disjoint_names=${3:-MID}
else
modprobe test_dynamic_debug dyndbg=+pm \
p_disjoint_bits=${1:-0} p_level_num=${2:-0}
# p_disjoint_names=${3:-MID} p_level_names=${4:-L3}
fi
# _submod should pick up kparams
echo MP test_dynamic_debug_submod dyndbg=+pmf
modprobe test_dynamic_debug_submod dyndbg=+pmf
}
unmod () {
rmmod test_dynamic_debug_submod
rmmod test_dynamic_debug
}
# The test:
submod_test () {
unmod
submod $*
sleep 1
note "above submod.s D2_* prdbgs should have printed"
note "because they are enabled here:"
ddgrep _submod
echo 1 > /sys/module/test_dynamic_debug/parameters/do_prints
note submod prdbgs should print here
echo 1 > /sys/module/test_dynamic_debug_submod/parameters/do_prints
}
# old-code: triggered jump-label init panic, fixed by doing
# dyndbg-init in notifier, after jump-label
submod_force () {
unmod
submod $*
sleep 1
# force all classes off, then on
note trigger toggled warning by turning off the supposed enabled prdbgs in submod
echo 0 > /sys/module/test_dynamic_debug/parameters/disjoint_bits
echo 0x2ff > /sys/module/test_dynamic_debug/parameters/disjoint_bits
note now theyre on
doprints
}
setup () {
echo dynbg-verbose-0, clearing kmsg, and running submod_test
vx 0
dmesg -W &
submod_test 7 7
ddcmd class V +mfl
ddcmd class V2 +tmfsl
ddcmd class V3 +mfsl
ddcmd class V4 +mfs
ddcmd class V5 +mf
ddcmd class V6 +m
doprints
}
Jim Cromie (22):
test-dyndbg: fixup CLASSMAP usage error
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-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code
dyndbg-API: fix CONFIG_DRM_USE_DYNAMIC_DEBUG regression
dyndbg: add for_each_boxed_vector
dyndbg: refactor ddebug_classparam_clamp_input
dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API
dyndbg-test: build it with just CONFIG_DYNAMIC_DEBUG_CORE
dyndbg-doc: add classmap info to howto
dyndbg: reserve flag bit _DPRINTK_FLAGS_PREFIX_CACHED
dyndbg: add _DPRINTK_FLAGS_INCL_LOOKUP
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
.../admin-guide/dynamic-debug-howto.rst | 60 ++-
MAINTAINERS | 2 +-
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 | 35 +-
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 | 12 +-
include/linux/dynamic_debug.h | 122 ++++--
kernel/module/main.c | 3 +
lib/Kconfig.debug | 10 +-
lib/Makefile | 4 +-
lib/dynamic_debug.c | 407 +++++++++++-------
lib/test_dynamic_debug.c | 137 +++---
lib/test_dynamic_debug_submod.c | 17 +
27 files changed, 546 insertions(+), 346 deletions(-)
create mode 100644 lib/test_dynamic_debug_submod.c
--
2.41.0
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