From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH] printk/tracing: Do not trace printk_nmi_enter()
Date: Fri, 7 Sep 2018 16:02:34 +0200 [thread overview]
Message-ID: <20180907140234.GG24106@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180907095533.5b5febc2@gandalf.local.home>
On Fri, Sep 07, 2018 at 09:55:33AM -0400, Steven Rostedt wrote:
> On Fri, 7 Sep 2018 15:45:32 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > Yes really, we should not muck with the IRQ state from NMI context.
>
> Right, and we didn't. Your patch didn't change anything, but allow for
It does, it kills lockdep before we get to mucking with the IRQ state.
> printk_nmi_enter/exit() to be traced by ftrace, but that's wrong to
> begin with because it ftrace_nmi_enter() hasn't been called yet.
That's a second bug :-) A better solution might be to inline that
function as well. A direct OR instruction is still way faster than a
CALL+RET.
prev parent reply other threads:[~2018-09-07 14:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 1:33 [PATCH] printk/tracing: Do not trace printk_nmi_enter() Steven Rostedt
2018-09-06 2:31 ` Sergey Senozhatsky
2018-09-06 9:04 ` Petr Mladek
2018-09-06 15:22 ` Steven Rostedt
2018-09-07 7:45 ` Peter Zijlstra
2018-09-07 8:28 ` Petr Mladek
2018-09-07 8:35 ` Sergey Senozhatsky
2018-09-07 13:47 ` Steven Rostedt
2018-09-07 9:30 ` Peter Zijlstra
2018-09-07 13:53 ` Steven Rostedt
2018-09-10 5:32 ` locking/lockdep: Fix NMI handling kbuild test robot
2018-09-07 7:34 ` [PATCH] printk/tracing: Do not trace printk_nmi_enter() Peter Zijlstra
2018-09-07 13:41 ` Steven Rostedt
2018-09-07 13:45 ` Peter Zijlstra
2018-09-07 13:55 ` Steven Rostedt
2018-09-07 14:01 ` Steven Rostedt
2018-09-07 14:03 ` Peter Zijlstra
2018-09-07 14:52 ` Sergey Senozhatsky
2018-09-07 14:02 ` Peter Zijlstra [this message]
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