[PATCH 1/2] kprobes: remove redundant address check

[PATCH 1/2] kprobes: remove redundant address check

[Namhyung Kim]

remove call to kernel_text_address() in register_jprobes()
because it is called right after in register_kprobe().

Signed-off-by: Namhyung Kim <namhyung@gmail.com>

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 282035f..8f96701 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1343,14 +1343,11 @@ int __kprobes register_jprobes(struct jprobe **jps, int num)
 		jp = jps[i];
 		addr = arch_deref_entry_point(jp->entry);
 
-		if (!kernel_text_address(addr))
-			ret = -EINVAL;
-		else {
-			/* Todo: Verify probepoint is a function entry point */
-			jp->kp.pre_handler = setjmp_pre_handler;
-			jp->kp.break_handler = longjmp_break_handler;
-			ret = register_kprobe(&jp->kp);
-		}
+		/* Todo: Verify probepoint is a function entry point */
+		jp->kp.pre_handler = setjmp_pre_handler;
+		jp->kp.break_handler = longjmp_break_handler;
+		ret = register_kprobe(&jp->kp);
+
 		if (ret < 0) {
 			if (i > 0)
 				unregister_jprobes(jps, i);
-- 
1.7.0.4

Re: [PATCH 1/2] kprobes: remove redundant address check

[Masami Hiramatsu]

Namhyung Kim wrote:
> remove call to kernel_text_address() in register_jprobes()
> because it is called right after in register_kprobe().

Indeed. Thank you for finding that! :)

> Signed-off-by: Namhyung Kim <namhyung@gmail.com>

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 282035f..8f96701 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1343,14 +1343,11 @@ int __kprobes register_jprobes(struct jprobe **jps, int num)
>  		jp = jps[i];
>  		addr = arch_deref_entry_point(jp->entry);
>  
> -		if (!kernel_text_address(addr))
> -			ret = -EINVAL;
> -		else {
> -			/* Todo: Verify probepoint is a function entry point */
> -			jp->kp.pre_handler = setjmp_pre_handler;
> -			jp->kp.break_handler = longjmp_break_handler;
> -			ret = register_kprobe(&jp->kp);
> -		}
> +		/* Todo: Verify probepoint is a function entry point */
> +		jp->kp.pre_handler = setjmp_pre_handler;
> +		jp->kp.break_handler = longjmp_break_handler;
> +		ret = register_kprobe(&jp->kp);
> +
>  		if (ret < 0) {
>  			if (i > 0)
>  				unregister_jprobes(jps, i);
-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com