From 683263a5e075aca81915a5abc0006a5435d3d54d Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sun, 4 Sep 2022 15:40:45 -0600 Subject: [PATCH] dyndbg: add test_dynamic_debug module Provide a simple module to allow testing DYNAMIC_DEBUG behavior. It calls do_prints() from module-init, and with a sysfs-node. dmesg -C dmesg -w & modprobe test_dynamic_debug dyndbg=+p echo 1 > /sys/module/dynamic_debug/parameters/verbose cat /sys/module/test_dynamic_debug/parameters/do_prints echo module test_dynamic_debug +mftl > /proc/dynamic_debug/control echo junk > /sys/module/test_dynamic_debug/parameters/do_prints Acked-by: Jason Baron Acked-by: Daniel Vetter Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-9-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- MAINTAINERS | 2 ++ lib/Kconfig.debug | 10 ++++++ lib/Makefile | 1 + lib/test_dynamic_debug.c | 70 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 83 insertions(+) create mode 100644 lib/test_dynamic_debug.c diff --git a/MAINTAINERS b/MAINTAINERS index 9d7f64dc0efe..8d8f99a5c279 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7205,6 +7205,8 @@ M: Jason Baron S: Maintained F: include/linux/dynamic_debug.h F: lib/dynamic_debug.c +M: Jim Cromie +F: lib/test_dynamic_debug.c DYNAMIC INTERRUPT MODERATION M: Tal Gilboa diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 072e4b289c13..43b49642cb08 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2546,6 +2546,16 @@ config TEST_STATIC_KEYS If unsure, say N. +config TEST_DYNAMIC_DEBUG + tristate "Test DYNAMIC_DEBUG" + depends on DYNAMIC_DEBUG + help + This module registers a tracer callback to count enabled + pr_debugs in a 'do_debugging' function, then alters their + enablements, calls the function, and compares counts. + + If unsure, say N. + config TEST_KMOD tristate "kmod stress tester" depends on m diff --git a/lib/Makefile b/lib/Makefile index 5927d7fa0806..338036b0b80c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -82,6 +82,7 @@ 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_PRINTF) += test_printf.o obj-$(CONFIG_TEST_SCANF) += test_scanf.o obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c new file mode 100644 index 000000000000..ba3882ca3e48 --- /dev/null +++ b/lib/test_dynamic_debug.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kernel module for testing dynamic_debug + * + * Authors: + * Jim Cromie + */ + +#define pr_fmt(fmt) "test_dd: " fmt + +#include + +static void do_prints(void); /* device under test */ + +/* run tests by reading or writing sysfs node */ + +static int param_set_do_prints(const char *instr, const struct kernel_param *kp) +{ + do_prints(); + return 0; +} + +static int param_get_do_prints(char *buffer, const struct kernel_param *kp) +{ + do_prints(); + return scnprintf(buffer, PAGE_SIZE, "did do_prints\n"); +} + +static const struct kernel_param_ops param_ops_do_prints = { + .set = param_set_do_prints, + .get = param_get_do_prints, +}; + +module_param_cb(do_prints, ¶m_ops_do_prints, NULL, 0600); + +static void do_alpha(void) +{ + pr_debug("do alpha\n"); +} +static void do_beta(void) +{ + pr_debug("do beta\n"); +} + +static void do_prints(void) +{ + do_alpha(); + do_beta(); +} + +static int __init test_dynamic_debug_init(void) +{ + pr_debug("init start\n"); + + do_prints(); + + pr_debug("init done\n"); + return 0; +} + +static void __exit test_dynamic_debug_exit(void) +{ + pr_debug("exiting\n"); +} + +module_init(test_dynamic_debug_init); +module_exit(test_dynamic_debug_exit); + +MODULE_AUTHOR("Jim Cromie "); +MODULE_LICENSE("GPL");