[PATCH -tip v3 1/7] kprobes: Improve smoke test to check preemptible

[Masami Hiramatsu]

Add preemptible check to each handler. Handlers are called with
non-preemtible, which is guaranteed by Documentation/kprobes.txt.

Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
---
 kernel/test_kprobes.c |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c
index 0dbab6d1acb4..47106a1e645a 100644
--- a/kernel/test_kprobes.c
+++ b/kernel/test_kprobes.c
@@ -34,6 +34,10 @@ static noinline u32 kprobe_target(u32 value)
 
 static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 {
+       if (preemptible()) {
+               handler_errors++;
+               pr_err("pre-handler is preemptible\n");
+       }
        preh_val = (rand1 / div_factor);
        return 0;
 }
@@ -41,6 +45,10 @@ static int kp_pre_handler(struct kprobe *p, struct pt_regs 
*regs)
 static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
                unsigned long flags)
 {
+       if (preemptible()) {
+               handler_errors++;
+               pr_err("post-handler is preemptible\n");
+       }
        if (preh_val != (rand1 / div_factor)) {
                handler_errors++;
                pr_err("incorrect value in post_handler\n");
@@ -156,6 +164,10 @@ static int test_kprobes(void)
 
 static u32 j_kprobe_target(u32 value)
 {
+       if (preemptible()) {
+               handler_errors++;
+               pr_err("jprobe-handler is preemptible\n");
+       }
        if (value != rand1) {
                handler_errors++;
                pr_err("incorrect value in jprobe handler\n");
@@ -232,6 +244,10 @@ static u32 krph_val;
 
 static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
+       if (preemptible()) {
+               handler_errors++;
+               pr_err("kretprobe entry handler is preemptible\n");
+       }
        krph_val = (rand1 / div_factor);
        return 0;
 }
@@ -240,6 +256,10 @@ static int return_handler(struct kretprobe_instance *ri, 
struct pt_regs *regs)
 {
        unsigned long ret = regs_return_value(regs);
 
+       if (preemptible()) {
+               handler_errors++;
+               pr_err("kretprobe return handler is preemptible\n");
+       }
        if (ret != (rand1 / div_factor)) {
                handler_errors++;
                pr_err("incorrect value in kretprobe handler\n");