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From: Andrew Morton <akpm@linux-foundation.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andi Kleen <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH] Support resetting WARN_ONCE for all architectures
Date: Fri, 3 Nov 2017 10:47:55 -0700	[thread overview]
Message-ID: <20171103104755.0fa2dba59f48df43d5bffb25@linux-foundation.org> (raw)
In-Reply-To: <878tfn7ldw.fsf@concordia.ellerman.id.au>

On Fri, 03 Nov 2017 20:38:03 +1100 Michael Ellerman <mpe@ellerman.id.au> wrote:

> Hi Andi,
> 
> Thanks for making it work with the flag, but ...
> 
> Andi Kleen <andi@firstfloor.org> writes:
> > diff --git a/lib/bug.c b/lib/bug.c
> > index a6a1137d06db..7cb2d41845f7 100644
> > --- a/lib/bug.c
> > +++ b/lib/bug.c
> > @@ -195,3 +195,24 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
> >  
> >  	return BUG_TRAP_TYPE_BUG;
> >  }
> > +
> > +static void clear_once_table(struct bug_entry *start, struct bug_entry *end)
> > +{
> > +	struct bug_entry *bug;
> > +
> > +	for (bug = start; bug < end; bug++)
> > +		bug->flags &= ~BUGFLAG_ONCE;
> 
> Clearing BUGFLAG_ONCE removes the once-ness permanently. ie. it becomes
> a WARN().
> 
> You should be clearing BUGFLAG_DONE, which is the flag that says this
> WARN has already triggered.

This?

--- a/lib/bug.c~support-resetting-warn_once-for-all-architectures-v2-fix-fix-fix
+++ a/lib/bug.c
@@ -202,7 +202,7 @@ static void clear_once_table(struct bug_
 	struct bug_entry *bug;
 
 	for (bug = start; bug < end; bug++)
-		bug->flags &= ~BUGFLAG_ONCE;
+		bug->flags &= ~BUGFLAG_DONE;
 }
 
 void generic_bug_clear_once(void)


And this is getting a bit nutty:

support-resetting-warn_once.patch
support-resetting-warn_once-checkpatch-fixes.patch
support-resetting-warn_once-for-all-architectures.patch
support-resetting-warn_once-for-all-architectures-v2.patch
support-resetting-warn_once-for-all-architectures-v2-fix.patch
support-resetting-warn_once-for-all-architectures-v2-fix-fix.patch
support-resetting-warn_once-for-all-architectures-v2-fix-fix-fix.patch

I'll push all this at Stephen later today.  Someone please tell me
whether this code actually works!

  reply	other threads:[~2017-11-03 17:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-19 20:46 Andi Kleen
2017-11-03  9:38 ` Michael Ellerman
2017-11-03 17:47   ` Andrew Morton [this message]
2017-11-06  0:18     ` Michael Ellerman
2017-11-06 21:36     ` Andi Kleen
2017-11-08  9:40       ` Michael Ellerman
2017-10-20 17:06 Andi Kleen

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