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[PATCH] tracing/kprobes: allow to create probe with a module name starting with a digit

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  [PATCH] tracing/kprobes: allow to create probe with a module name starting with a digit Sabrina Dubroca <sd@queasysnail.net> - 2017-06-22 11:30 +0200
    Re: [PATCH] tracing/kprobes: allow to create probe with a module  name starting with a digit Masami Hiramatsu <mhiramat@kernel.org> - 2017-06-27 10:40 +0200
      Re: [PATCH] tracing/kprobes: allow to create probe with a module  name starting with a digit Steven Rostedt <rostedt@goodmis.org> - 2017-06-27 16:10 +0200
        Re: [PATCH] tracing/kprobes: allow to create probe with a module  name starting with a digit Masami Hiramatsu <mhiramat@kernel.org> - 2017-06-28 00:10 +0200

#1672457 — [PATCH] tracing/kprobes: allow to create probe with a module name starting with a digit

Always try to parse an address, since kstrtoul() will safely fail when
given a symbol as input. If that fails (which will be the case for a
symbol), try to parse a symbol instead.

This allows creating a probe such as:

    p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0

Which is necessary for this command to work:

    perf probe -m 8021q -a vlan_gro_receive

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
 kernel/trace/trace_kprobe.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index c129fca6ec99..b53c8d369163 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -707,20 +707,16 @@ static int create_trace_kprobe(int argc, char **argv)
 		pr_info("Probe point is not specified.\n");
 		return -EINVAL;
 	}
-	if (isdigit(argv[1][0])) {
-		/* an address specified */
-		ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
-		if (ret) {
-			pr_info("Failed to parse address.\n");
-			return ret;
-		}
-	} else {
+
+	/* try to parse an address. if that fails, try to read the
+	 * input as a symbol. */
+	if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 		/* a symbol specified */
 		symbol = argv[1];
 		/* TODO: support .init module functions */
 		ret = traceprobe_split_symbol_offset(symbol, &offset);
 		if (ret) {
-			pr_info("Failed to parse symbol.\n");
+			pr_info("Failed to parse either an address or a symbol.\n");
 			return ret;
 		}
 		if (offset && is_return &&
-- 
2.13.1

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#1675412 — Re: [PATCH] tracing/kprobes: allow to create probe with a module name starting with a digit

On Thu, 22 Jun 2017 11:24:42 +0200
Sabrina Dubroca <sd@queasysnail.net> wrote:

> Always try to parse an address, since kstrtoul() will safely fail when
> given a symbol as input. If that fails (which will be the case for a
> symbol), try to parse a symbol instead.
> 
> This allows creating a probe such as:
> 
>     p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0
> 
> Which is necessary for this command to work:
> 
>     perf probe -m 8021q -a vlan_gro_receive
> 

Ah, I forgot that case.
Nice catch!

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

Thanks!

> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> ---
>  kernel/trace/trace_kprobe.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index c129fca6ec99..b53c8d369163 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -707,20 +707,16 @@ static int create_trace_kprobe(int argc, char **argv)
>  		pr_info("Probe point is not specified.\n");
>  		return -EINVAL;
>  	}
> -	if (isdigit(argv[1][0])) {
> -		/* an address specified */
> -		ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
> -		if (ret) {
> -			pr_info("Failed to parse address.\n");
> -			return ret;
> -		}
> -	} else {
> +
> +	/* try to parse an address. if that fails, try to read the
> +	 * input as a symbol. */
> +	if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
>  		/* a symbol specified */
>  		symbol = argv[1];
>  		/* TODO: support .init module functions */
>  		ret = traceprobe_split_symbol_offset(symbol, &offset);
>  		if (ret) {
> -			pr_info("Failed to parse symbol.\n");
> +			pr_info("Failed to parse either an address or a symbol.\n");
>  			return ret;
>  		}
>  		if (offset && is_return &&
> -- 
> 2.13.1
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

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#1675729 — Re: [PATCH] tracing/kprobes: allow to create probe with a module name starting with a digit

On Tue, 27 Jun 2017 17:38:30 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> On Thu, 22 Jun 2017 11:24:42 +0200
> Sabrina Dubroca <sd@queasysnail.net> wrote:
> 
> > Always try to parse an address, since kstrtoul() will safely fail when
> > given a symbol as input. If that fails (which will be the case for a
> > symbol), try to parse a symbol instead.
> > 
> > This allows creating a probe such as:
> > 
> >     p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0
> > 
> > Which is necessary for this command to work:
> > 
> >     perf probe -m 8021q -a vlan_gro_receive
> >   
> 
> Ah, I forgot that case.
> Nice catch!
> 
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
>

Thanks Masami,

I can take this. Should this go to stable?

-- Steve

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#1676213 — Re: [PATCH] tracing/kprobes: allow to create probe with a module name starting with a digit

On Tue, 27 Jun 2017 10:07:45 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Tue, 27 Jun 2017 17:38:30 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > On Thu, 22 Jun 2017 11:24:42 +0200
> > Sabrina Dubroca <sd@queasysnail.net> wrote:
> > 
> > > Always try to parse an address, since kstrtoul() will safely fail when
> > > given a symbol as input. If that fails (which will be the case for a
> > > symbol), try to parse a symbol instead.
> > > 
> > > This allows creating a probe such as:
> > > 
> > >     p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0
> > > 
> > > Which is necessary for this command to work:
> > > 
> > >     perf probe -m 8021q -a vlan_gro_receive
> > >   
> > 
> > Ah, I forgot that case.
> > Nice catch!
> > 
> > Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
> >
> 
> Thanks Masami,
> 
> I can take this. Should this go to stable?

Yes, it should go to stable. 

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

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