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From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Martin KaFai Lau <martin.lau@linux.dev>,
	bpf@vger.kernel.org, Sven Schnelle <svens@linux.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>
Subject: Re: [PATCH v2 2/9] bpf/btf: tracing: Move finding func-proto API and getting func-param API to BTF
Date: Mon, 17 Jul 2023 19:51:29 -0400	[thread overview]
Message-ID: <20230717195129.14759151@gandalf.local.home> (raw)
In-Reply-To: <20230718084634.7746b16b470f5fa1b0d99521@kernel.org>

On Tue, 18 Jul 2023 08:46:34 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> > > + * Get function parameter with the number of parameters.
> > > + * This can return NULL if the function has no parameters.  
> > 
> >   " It can return EINVAL if this function's parameters are NULL."  
> 
> No, as you can see the code, if btf_type_vlen(func_proto) returns 0 (means
> the function proto type has no parameters), btf_get_func_param() returns
> NULL. This is important point because user needs to use IS_ERR_OR_NULL(ret)
> instead of IS_ERR(ret).

I didn't mean to replace what you had, I meant you left that part out. In
other words, you have to check for IS_ERR_OR_NULL(ret), not just "!ret".

-- Steve

> >   
> > > + */
> > > +const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr)
> > > +{
> > > +	if (!func_proto || !nr)
> > > +		return ERR_PTR(-EINVAL);
> > > +

  parent reply	other threads:[~2023-07-17 23:51 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-17 15:23 [PATCH v2 0/9] tracing: Improbe BTF support on probe events Masami Hiramatsu (Google)
2023-07-17 15:23 ` [PATCH v2 1/9] tracing/probes: Fix to add NULL check for BTF APIs Masami Hiramatsu (Google)
2023-07-17 15:23 ` [PATCH v2 2/9] bpf/btf: tracing: Move finding func-proto API and getting func-param API to BTF Masami Hiramatsu (Google)
2023-07-17 18:39   ` Steven Rostedt
2023-07-17 23:46     ` Masami Hiramatsu
2023-07-17 23:51       ` Alexei Starovoitov
2023-07-18  1:03         ` Masami Hiramatsu
2023-07-17 23:51       ` Steven Rostedt [this message]
2023-07-18  1:02         ` Masami Hiramatsu
2023-07-18  2:40   ` Donglin Peng
2023-07-18 10:44     ` Masami Hiramatsu
2023-07-18 13:56       ` Masami Hiramatsu
2023-07-18 17:11         ` Alexei Starovoitov
2023-07-18 23:03           ` Masami Hiramatsu
2023-07-18 23:12             ` Alexei Starovoitov
2023-07-19 15:17               ` Masami Hiramatsu
2023-07-19  2:09             ` Donglin Peng
2023-07-19 15:15               ` Masami Hiramatsu
2023-07-19 12:36   ` Alan Maguire
2023-07-19 15:24     ` Masami Hiramatsu
2023-07-19 15:49       ` Alan Maguire
2023-07-17 15:23 ` [PATCH v2 3/9] bpf/btf: Add a function to search a member of a struct/union Masami Hiramatsu (Google)
2023-07-20 22:34   ` Alan Maguire
2023-07-21 14:22     ` Masami Hiramatsu
2023-07-17 15:23 ` [PATCH v2 4/9] tracing/probes: Support BTF based data structure field access Masami Hiramatsu (Google)
2023-07-20 22:51   ` Alan Maguire
2023-07-21 14:22     ` Masami Hiramatsu
2023-07-17 15:24 ` [PATCH v2 5/9] tracing/probes: Support BTF field access from $retval Masami Hiramatsu (Google)
2023-07-17 15:24 ` [PATCH v2 6/9] tracing/probes: Add string type check with BTF Masami Hiramatsu (Google)
2023-07-17 15:24 ` [PATCH v2 7/9] tracing/fprobe-event: Assume fprobe is a return event by $retval Masami Hiramatsu (Google)
2023-07-17 15:24 ` [PATCH v2 8/9] selftests/ftrace: Add BTF fields access testcases Masami Hiramatsu (Google)
2023-07-20 23:00   ` Alan Maguire
2023-07-21  1:42     ` Masami Hiramatsu
2023-07-17 15:24 ` [PATCH v2 9/9] Documentation: tracing: Update fprobe event example with BTF field Masami Hiramatsu (Google)
2023-07-20 22:53   ` Alan Maguire
2023-07-21 13:58     ` Masami Hiramatsu
2023-07-19  9:02 ` [PATCH v2 0/9] tracing: Improbe BTF support on probe events Alan Maguire
2023-07-19 16:01   ` Masami Hiramatsu
2023-07-20 21:50     ` Alan Maguire
2023-07-25 23:45       ` Masami Hiramatsu

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