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authorJim Cromie <jim.cromie@gmail.com>2022-09-05 00:40:45 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-09-07 17:58:23 +0300
commit683263a5e075aca81915a5abc0006a5435d3d54d (patch)
tree247df622efd57da766f2b8c7ee1a151011007538 /lib
parente75ef56f74965f426dd819a41336b640ffdd8fbc (diff)
downloadlinux-683263a5e075aca81915a5abc0006a5435d3d54d.tar.xz
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 <jbaron@akamai.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Link: https://lore.kernel.org/r/20220904214134.408619-9-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug10
-rw-r--r--lib/Makefile1
-rw-r--r--lib/test_dynamic_debug.c70
3 files changed, 81 insertions, 0 deletions
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 <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");