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Subject[PATCH v5 08/33] dyndbg: add test_dynamic_debug module
Date
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

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.com>
---
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 64379c699903..a14fc4b6a10b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7093,6 +7093,8 @@ M: Jason Baron <jbaron@akamai.com>
S: Maintained
F: include/linux/dynamic_debug.h
F: lib/dynamic_debug.c
+M: Jim Cromie <jim.cromie@gmail.com>
+F: lib/test_dynamic_debug.c

DYNAMIC INTERRUPT MODERATION
M: Tal Gilboa <talgi@nvidia.com>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2e24db4bff19..ca5978e1d18a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2529,6 +2529,16 @@ 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 f99bf61f8bbc..9c316df868de 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 <jim.cromie@gmail.com>
+ */
+
+#define pr_fmt(fmt) "test_dd: " fmt
+
+#include <linux/module.h>
+
+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, &param_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 <jim.cromie@gmail.com>");
+MODULE_LICENSE("GPL");
--
2.37.1
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