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Message-ID: <50399556C9727B4D88A595C8584AAB37524B7E65@GSjpTKYDCembx32.service.hitachi.net>
Date: Wed, 12 Aug 2015 21:47:18 +0000
From: 平松雅巳 / HIRAMATU,MASAMI
<masami.hiramatsu.pt@...achi.com>
To: "'Steve Capper'" <steve.capper@...aro.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "will.deacon@....com" <will.deacon@....com>,
"sandeepa.s.prabhu@...il.com" <sandeepa.s.prabhu@...il.com>,
"dave.long@...aro.org" <dave.long@...aro.org>,
"catalin.marinas@....com" <catalin.marinas@....com>,
"linux@....linux.org.uk" <linux@....linux.org.uk>,
"wcohen@...hat.com" <wcohen@...hat.com>,
"tixy@...aro.org" <tixy@...aro.org>,
"ananth@...ibm.com" <ananth@...ibm.com>,
"anil.s.keshavamurthy@...el.com" <anil.s.keshavamurthy@...el.com>,
"davem@...emloft.net" <davem@...emloft.net>,
"broonie@...nel.org" <broonie@...nel.org>
Subject: RE: [PATCH] kprobes: Update examples to target _do_fork
> From: Steve Capper [mailto:steve.capper@...aro.org]
>
> In commit 3033f14ab78c ("clone: support passing tls argument via C
> rather than pt_regs magic"), the kernel calls _do_fork in places where
> it previously called do_fork.
>
> Unfortunately, the kprobe examples target do_fork; thus no events
> appear to fire when one runs the example modules.
>
> This commit updates the kprobe example code s.t. _do_fork is targeted
> instead, and the examples work as expected.
Oops, right! I've found it on ftrace-test, but missed on kprobes examples :(
>
> Signed-off-by: Steve Capper <steve.capper@...aro.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Thank you!
> ---
> samples/kprobes/jprobe_example.c | 8 ++++----
> samples/kprobes/kprobe_example.c | 2 +-
> samples/kprobes/kretprobe_example.c | 2 +-
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/samples/kprobes/jprobe_example.c b/samples/kprobes/jprobe_example.c
> index 9119ac6..11dd54b 100644
> --- a/samples/kprobes/jprobe_example.c
> +++ b/samples/kprobes/jprobe_example.c
> @@ -23,9 +23,9 @@
> */
>
> /* Proxy routine having the same arguments as actual do_fork() routine */
> -static long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
> +static long j_do_fork(unsigned long clone_flags, unsigned long stack_start,
> unsigned long stack_size, int __user *parent_tidptr,
> - int __user *child_tidptr)
> + int __user *child_tidptr, unsigned long tls)
> {
> pr_info("jprobe: clone_flags = 0x%lx, stack_start = 0x%lx "
> "stack_size = 0x%lx\n", clone_flags, stack_start, stack_size);
> @@ -36,9 +36,9 @@ static long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
> }
>
> static struct jprobe my_jprobe = {
> - .entry = jdo_fork,
> + .entry = j_do_fork,
> .kp = {
> - .symbol_name = "do_fork",
> + .symbol_name = "_do_fork",
> },
> };
>
> diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
> index 51d459c..597e101 100644
> --- a/samples/kprobes/kprobe_example.c
> +++ b/samples/kprobes/kprobe_example.c
> @@ -16,7 +16,7 @@
>
> /* For each probe you need to allocate a kprobe structure */
> static struct kprobe kp = {
> - .symbol_name = "do_fork",
> + .symbol_name = "_do_fork",
> };
>
> /* kprobe pre_handler: called just before the probed instruction is executed */
> diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
> index 1041b67..a270535 100644
> --- a/samples/kprobes/kretprobe_example.c
> +++ b/samples/kprobes/kretprobe_example.c
> @@ -25,7 +25,7 @@
> #include <linux/limits.h>
> #include <linux/sched.h>
>
> -static char func_name[NAME_MAX] = "do_fork";
> +static char func_name[NAME_MAX] = "_do_fork";
> module_param_string(func, func_name, NAME_MAX, S_IRUGO);
> MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the"
> " function's execution time");
> --
> 2.1.0
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