linux-kernel - Re: [PATCH v2] printk: Use the main logbuf in NMI when logbuf

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Date:   Fri, 19 May 2017 13:38:15 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Russell King <rmk+kernel@....linux.org.uk>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Chris Metcalf <cmetcalf@...hip.com>, x86@...nel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] printk: Use the main logbuf in NMI when logbuf_lock
 is available

On (05/19/17 11:58), Sergey Senozhatsky wrote:
> >  void printk_nmi_exit(void)
> >  {
> > -	this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK);
> > +	this_cpu_and(printk_context,
> > +		     ~(PRINTK_NMI_CONTEXT_MASK ||
> > +		       PRINTK_NMI_DEFERRED_CONTEXT_MASK));
> >  }

[..]

> the problem is that
> 
> 	`PRINTK_NMI_CONTEXT_MASK || PRINTK_NMI_DEFERRED_CONTEXT_MASK' is 0x01

d'oh... forgot to copy-paste this...

---

diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index 6fec9cfb9a69..b6ff3fe4370a 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -324,7 +324,7 @@ void printk_nmi_enter(void)
 void printk_nmi_exit(void)
 {
        this_cpu_and(printk_context,
-                    ~(PRINTK_NMI_CONTEXT_MASK ||
+                    ~(PRINTK_NMI_CONTEXT_MASK |
                       PRINTK_NMI_DEFERRED_CONTEXT_MASK));
 }
 
---

	-ss