2020-08-05 17:24:13

by Muchun Song

Subject: [PATCH] kprobes: fix compiler warning for !CONFIG_KPROBES_ON_FTRACE

Fix compiler warning(as show below) for !CONFIG_KPROBES_ON_FTRACE.

kernel/kprobes.c: In function 'kill_kprobe':
kernel/kprobes.c:1116:33: warning: statement with no effect
[-Wunused-value]
1116 | #define disarm_kprobe_ftrace(p) (-ENODEV)
| ^
kernel/kprobes.c:2154:3: note: in expansion of macro
'disarm_kprobe_ftrace'
2154 | disarm_kprobe_ftrace(p);

Link: https://lore.kernel.org/r/[email protected]

Reported-by: Stephen Rothwell <[email protected]>
Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
Signed-off-by: Muchun Song <[email protected]>
---
kernel/kprobes.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 503add629599..d36e2b017588 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1114,9 +1114,20 @@ static int disarm_kprobe_ftrace(struct kprobe *p)
ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
}
#else /* !CONFIG_KPROBES_ON_FTRACE */
-#define prepare_kprobe(p) arch_prepare_kprobe(p)
-#define arm_kprobe_ftrace(p) (-ENODEV)
-#define disarm_kprobe_ftrace(p) (-ENODEV)
+static inline int prepare_kprobe(struct kprobe *p)
+{
+ return arch_prepare_kprobe(p);
+}
+
+static inline int arm_kprobe_ftrace(struct kprobe *p)
+{
+ return -ENODEV;
+}
+
+static inline int disarm_kprobe_ftrace(struct kprobe *p)
+{
+ return -ENODEV;
+}
#endif

/* Arm a kprobe with text_mutex */
--
2.11.0

2020-08-06 01:31:11

by Masami Hiramatsu

Subject: Re: [PATCH] kprobes: fix compiler warning for !CONFIG_KPROBES_ON_FTRACE

On Thu, 6 Aug 2020 01:20:46 +0800
Muchun Song <[email protected]> wrote:

> Fix compiler warning(as show below) for !CONFIG_KPROBES_ON_FTRACE.
>
> kernel/kprobes.c: In function 'kill_kprobe':
> kernel/kprobes.c:1116:33: warning: statement with no effect
> [-Wunused-value]
> 1116 | #define disarm_kprobe_ftrace(p) (-ENODEV)
> | ^
> kernel/kprobes.c:2154:3: note: in expansion of macro
> 'disarm_kprobe_ftrace'
> 2154 | disarm_kprobe_ftrace(p);
>
> Link: https://lore.kernel.org/r/[email protected]
>
> Reported-by: Stephen Rothwell <[email protected]>
> Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
> Signed-off-by: Muchun Song <[email protected]>

Looks good to me.

Acked-by: Masami Hiramatsu <[email protected]>

Thank you!

> ---
> kernel/kprobes.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 503add629599..d36e2b017588 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1114,9 +1114,20 @@ static int disarm_kprobe_ftrace(struct kprobe *p)
> ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
> }
> #else /* !CONFIG_KPROBES_ON_FTRACE */
> -#define prepare_kprobe(p) arch_prepare_kprobe(p)
> -#define arm_kprobe_ftrace(p) (-ENODEV)
> -#define disarm_kprobe_ftrace(p) (-ENODEV)
> +static inline int prepare_kprobe(struct kprobe *p)
> +{
> + return arch_prepare_kprobe(p);
> +}
> +
> +static inline int arm_kprobe_ftrace(struct kprobe *p)
> +{
> + return -ENODEV;
> +}
> +
> +static inline int disarm_kprobe_ftrace(struct kprobe *p)
> +{
> + return -ENODEV;
> +}
> #endif
>
> /* Arm a kprobe with text_mutex */
> --
> 2.11.0
>


--
Masami Hiramatsu <[email protected]>

2020-08-06 05:44:13

by John Fastabend

Subject: RE: [PATCH] kprobes: fix compiler warning for !CONFIG_KPROBES_ON_FTRACE

Muchun Song wrote:
> Fix compiler warning(as show below) for !CONFIG_KPROBES_ON_FTRACE.
>
> kernel/kprobes.c: In function 'kill_kprobe':
> kernel/kprobes.c:1116:33: warning: statement with no effect
> [-Wunused-value]
> 1116 | #define disarm_kprobe_ftrace(p) (-ENODEV)
> | ^
> kernel/kprobes.c:2154:3: note: in expansion of macro
> 'disarm_kprobe_ftrace'
> 2154 | disarm_kprobe_ftrace(p);
>
> Link: https://lore.kernel.org/r/[email protected]
>
> Reported-by: Stephen Rothwell <[email protected]>
> Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
> Signed-off-by: Muchun Song <[email protected]>
> ---

Acked-by: John Fastabend <[email protected]>