2021-12-22 10:03:51

by Jiri Olsa

Subject: [PATCH] kprobe: Remove kprobe_instance and its related functions

The last user od kprobe_instance got removed in [1],
now it just occupies space, removing it.

[1] ec6aba3d2be1 ("kprobes: Remove kprobe::fault_handler")

Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
---
kernel/kprobes.c | 24 ++----------------------
1 file changed, 2 insertions(+), 22 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 21eccc961bba..d20ae8232835 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -62,7 +62,6 @@ static bool kprobes_all_disarmed;

/* This protects 'kprobe_table' and 'optimizing_list' */
static DEFINE_MUTEX(kprobe_mutex);
-static DEFINE_PER_CPU(struct kprobe *, kprobe_instance);

kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
unsigned int __unused)
@@ -353,17 +352,6 @@ struct kprobe_insn_cache kprobe_optinsn_slots = {
#endif
#endif

-/* We have preemption disabled.. so it is safe to use __ versions */
-static inline void set_kprobe_instance(struct kprobe *kp)
-{
- __this_cpu_write(kprobe_instance, kp);
-}
-
-static inline void reset_kprobe_instance(void)
-{
- __this_cpu_write(kprobe_instance, NULL);
-}
-
/*
* This routine is called either:
* - under the 'kprobe_mutex' - during kprobe_[un]register().
@@ -421,11 +409,8 @@ void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
struct kprobe *kp;

list_for_each_entry_rcu(kp, &p->list, list) {
- if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
- set_kprobe_instance(kp);
+ if (kp->pre_handler && likely(!kprobe_disabled(kp)))
kp->pre_handler(kp, regs);
- }
- reset_kprobe_instance();
}
}
NOKPROBE_SYMBOL(opt_pre_handler);
@@ -1177,11 +1162,9 @@ static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)

list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
- set_kprobe_instance(kp);
if (kp->pre_handler(kp, regs))
return 1;
}
- reset_kprobe_instance();
}
return 0;
}
@@ -1193,11 +1176,8 @@ static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
struct kprobe *kp;

list_for_each_entry_rcu(kp, &p->list, list) {
- if (kp->post_handler && likely(!kprobe_disabled(kp))) {
- set_kprobe_instance(kp);
+ if (kp->post_handler && likely(!kprobe_disabled(kp)))
kp->post_handler(kp, regs, flags);
- reset_kprobe_instance();
- }
}
}
NOKPROBE_SYMBOL(aggr_post_handler);
--
2.33.1

2021-12-22 14:28:28

by Masami Hiramatsu

Subject: Re: [PATCH] kprobe: Remove kprobe_instance and its related functions

On Wed, 22 Dec 2021 11:03:45 +0100
Jiri Olsa <[email protected]> wrote:

> The last user od kprobe_instance got removed in [1],
> now it just occupies space, removing it.
>
> [1] ec6aba3d2be1 ("kprobes: Remove kprobe::fault_handler")
>

Good catch! Thank you very much!

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


> Cc: Peter Zijlstra <[email protected]>
> Signed-off-by: Jiri Olsa <[email protected]>
> ---
> kernel/kprobes.c | 24 ++----------------------
> 1 file changed, 2 insertions(+), 22 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 21eccc961bba..d20ae8232835 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -62,7 +62,6 @@ static bool kprobes_all_disarmed;
>
> /* This protects 'kprobe_table' and 'optimizing_list' */
> static DEFINE_MUTEX(kprobe_mutex);
> -static DEFINE_PER_CPU(struct kprobe *, kprobe_instance);
>
> kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
> unsigned int __unused)
> @@ -353,17 +352,6 @@ struct kprobe_insn_cache kprobe_optinsn_slots = {
> #endif
> #endif
>
> -/* We have preemption disabled.. so it is safe to use __ versions */
> -static inline void set_kprobe_instance(struct kprobe *kp)
> -{
> - __this_cpu_write(kprobe_instance, kp);
> -}
> -
> -static inline void reset_kprobe_instance(void)
> -{
> - __this_cpu_write(kprobe_instance, NULL);
> -}
> -
> /*
> * This routine is called either:
> * - under the 'kprobe_mutex' - during kprobe_[un]register().
> @@ -421,11 +409,8 @@ void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
> struct kprobe *kp;
>
> list_for_each_entry_rcu(kp, &p->list, list) {
> - if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
> - set_kprobe_instance(kp);
> + if (kp->pre_handler && likely(!kprobe_disabled(kp)))
> kp->pre_handler(kp, regs);
> - }
> - reset_kprobe_instance();
> }
> }
> NOKPROBE_SYMBOL(opt_pre_handler);
> @@ -1177,11 +1162,9 @@ static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
>
> list_for_each_entry_rcu(kp, &p->list, list) {
> if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
> - set_kprobe_instance(kp);
> if (kp->pre_handler(kp, regs))
> return 1;
> }
> - reset_kprobe_instance();
> }
> return 0;
> }
> @@ -1193,11 +1176,8 @@ static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
> struct kprobe *kp;
>
> list_for_each_entry_rcu(kp, &p->list, list) {
> - if (kp->post_handler && likely(!kprobe_disabled(kp))) {
> - set_kprobe_instance(kp);
> + if (kp->post_handler && likely(!kprobe_disabled(kp)))
> kp->post_handler(kp, regs, flags);
> - reset_kprobe_instance();
> - }
> }
> }
> NOKPROBE_SYMBOL(aggr_post_handler);
> --
> 2.33.1
>


--
Masami Hiramatsu <[email protected]>

2021-12-24 06:32:50

by Christoph Hellwig

Subject: Re: [PATCH] kprobe: Remove kprobe_instance and its related functions

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>