lib/test_fprobe: Add a test case for nr_maxactive

Add a test case for nr_maxactive. If the number of active
functions is more than nr_maxactive, it must be skipped.

Link: https://lkml.kernel.org/r/167526698856.433354.4430007340787176666.stgit@mhiramat.roam.corp.google.com
Cc: Florent Revest <revest@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c
index 6c7ef5a..4b37d70 100644 (file)
--- a/lib/test_fprobe.c
+++ b/lib/test_fprobe.c
@@ -17,8 +17,10 @@ static u32 rand1, entry_val, exit_val;
 /* Use indirect calls to avoid inlining the target functions */
 static u32 (*target)(u32 value);
 static u32 (*target2)(u32 value);
+static u32 (*target_nest)(u32 value, u32 (*nest)(u32));
 static unsigned long target_ip;
 static unsigned long target2_ip;
+static unsigned long target_nest_ip;
 
 static noinline u32 fprobe_selftest_target(u32 value)
 {
@@ -30,6 +32,11 @@ static noinline u32 fprobe_selftest_target2(u32 value)
        return (value / div_factor) + 1;
 }
 
+static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
+{
+       return nest(value + 2);
+}
+
 static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip,
                                     struct pt_regs *regs, void *data)
 {
@@ -67,6 +74,19 @@ static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
                KUNIT_EXPECT_NULL(current_test, data);
 }
 
+static notrace void nest_entry_handler(struct fprobe *fp, unsigned long ip,
+                                    struct pt_regs *regs, void *data)
+{
+       KUNIT_EXPECT_FALSE(current_test, preemptible());
+}
+
+static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
+                                   struct pt_regs *regs, void *data)
+{
+       KUNIT_EXPECT_FALSE(current_test, preemptible());
+       KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);
+}
+
 /* Test entry only (no rethook) */
 static void test_fprobe_entry(struct kunit *test)
 {
@@ -163,6 +183,25 @@ static void test_fprobe_data(struct kunit *test)
        KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
 }
 
+/* Test nr_maxactive */
+static void test_fprobe_nest(struct kunit *test)
+{
+       static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_nest_target"};
+       struct fprobe fp = {
+               .entry_handler = nest_entry_handler,
+               .exit_handler = nest_exit_handler,
+               .nr_maxactive = 1,
+       };
+
+       current_test = test;
+       KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
+
+       target_nest(rand1, target);
+       KUNIT_EXPECT_EQ(test, 1, fp.nmissed);
+
+       KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
+}
+
 static unsigned long get_ftrace_location(void *func)
 {
        unsigned long size, addr = (unsigned long)func;
@@ -178,8 +217,10 @@ static int fprobe_test_init(struct kunit *test)
        rand1 = get_random_u32_above(div_factor);
        target = fprobe_selftest_target;
        target2 = fprobe_selftest_target2;
+       target_nest = fprobe_selftest_nest_target;
        target_ip = get_ftrace_location(target);
        target2_ip = get_ftrace_location(target2);
+       target_nest_ip = get_ftrace_location(target_nest);
 
        return 0;
 }
@@ -189,6 +230,7 @@ static struct kunit_case fprobe_testcases[] = {
        KUNIT_CASE(test_fprobe),
        KUNIT_CASE(test_fprobe_syms),
        KUNIT_CASE(test_fprobe_data),
+       KUNIT_CASE(test_fprobe_nest),
        {}
 };