From: Peter Zijlstra <peterz@infradead.org>
To: 王贇 <yun.wang@linux.alibaba.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
open list <linux-kernel@vger.kernel.org>,
Jiri Olsa <jolsa@redhat.com>
Subject: Re: [RESEND PATCH v2] trace: prevent preemption in perf_ftrace_function_call()
Date: Mon, 11 Oct 2021 10:48:27 +0200 [thread overview]
Message-ID: <YWP6W7Be0Yp6egsn@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YWP2rtX9Ol9dZc/l@hirez.programming.kicks-ass.net>
On Mon, Oct 11, 2021 at 10:32:46AM +0200, Peter Zijlstra wrote:
> diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
> index a9f9c5714e65..ca12e2d8e060 100644
> --- a/include/linux/trace_recursion.h
> +++ b/include/linux/trace_recursion.h
> @@ -214,7 +214,14 @@ static __always_inline void trace_clear_recursion(int bit)
> static __always_inline int ftrace_test_recursion_trylock(unsigned long ip,
> unsigned long parent_ip)
> {
> - return trace_test_and_set_recursion(ip, parent_ip, TRACE_FTRACE_START, TRACE_FTRACE_MAX);
> + bool ret;
> +
> + preempt_disable_notrace();
> + ret = trace_test_and_set_recursion(ip, parent_ip, TRACE_FTRACE_START, TRACE_FTRACE_MAX);
> + if (!ret)
> + preempt_enable_notrace();
> +
> + return ret;
> }
>
> /**
Oh, I might've gotten that wrong, I assumed regular trylock semantics,
but it doesn't look like that's right.
next prev parent reply other threads:[~2021-10-11 8:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-28 3:12 [RESEND PATCH v2] trace: prevent preemption in perf_ftrace_function_call() 王贇
2021-10-09 0:03 ` Steven Rostedt
2021-10-11 2:38 ` 王贇
2021-10-11 8:32 ` Peter Zijlstra
2021-10-11 8:48 ` Peter Zijlstra [this message]
2021-10-11 9:39 ` 王贇
2021-10-11 14:45 ` Peter Zijlstra
2021-10-12 5:51 ` 王贇
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