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SubjectRe: [PATCH 1/3] powerpc: kprobes: add support for KPROBES_ON_FTRACE
Hi Naveen,

On Wed, 15 Feb 2017 00:28:34 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:

> diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
> index e51a045f3d3b..a8f414a0b141 100644
> --- a/arch/powerpc/kernel/optprobes.c
> +++ b/arch/powerpc/kernel/optprobes.c
> @@ -70,6 +70,9 @@ static unsigned long can_optimize(struct kprobe *p)
> struct instruction_op op;
> unsigned long nip = 0;
>
> + if (unlikely(kprobe_ftrace(p)))
> + return 0;
> +

Hmm, this should not be checked in arch-depend code, since it may duplicate
code in each arch. Please try below.

Thanks,

commit 897bb304974c1b0c19a4274fea220b175b07f353
Author: Masami Hiramatsu <mhiramat@kernel.org>
Date: Wed Feb 15 15:48:14 2017 +0900

kprobes: Skip preparing optprobe if the probe is ftrace-based

Skip preparing optprobe if the probe is ftrace-based, since
anyway, it must not be optimized (or already optimized by
ftrace).

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ebb4dad..546a8b1 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -746,13 +746,20 @@ static void kill_optimized_kprobe(struct kprobe *p)
arch_remove_optimized_kprobe(op);
}

+static inline
+void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
+{
+ if (!kprobe_ftrace(p))
+ arch_prepare_optimized_kprobe(op, p);
+}
+
/* Try to prepare optimized instructions */
static void prepare_optimized_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;

op = container_of(p, struct optimized_kprobe, kp);
- arch_prepare_optimized_kprobe(op, p);
+ __prepare_optimized_kprobe(op, p);
}

/* Allocate new optimized_kprobe and try to prepare optimized instructions */
@@ -766,7 +773,7 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)

INIT_LIST_HEAD(&op->list);
op->kp.addr = p->addr;
- arch_prepare_optimized_kprobe(op, p);
+ __prepare_optimized_kprobe(op, p);

return &op->kp;
}


--
Masami Hiramatsu <mhiramat@kernel.org>

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