linux-kernel - Re: [PATCH] Support resetting WARN

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Date:   Fri, 03 Nov 2017 20:38:03 +1100
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Andi Kleen <andi@...stfloor.org>, akpm@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH] Support resetting WARN_ONCE for all architectures

Hi Andi,

Thanks for making it work with the flag, but ...

Andi Kleen <andi@...stfloor.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.

cheers