linux-kernel - Re: [PATCH RFC 2/2] genirq/matrix: WARN_ON_ONCE() when cm->allocated/m->total

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Date:   Fri, 19 Mar 2021 10:59:58 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org
Cc:     Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC 2/2] genirq/matrix: WARN_ON_ONCE() when
 cm->allocated/m->total_allocated go negative

Thomas Gleixner <tglx@...utronix.de> writes:

> On Thu, Mar 18 2021 at 08:58, Vitaly Kuznetsov wrote:
>> Thomas Gleixner <tglx@...utronix.de> writes:
>>> There is a way more useful way to handle this. In such a case the bit is
>>> NOT set in the alloc map. So:
>>>
>>>     if (!WARN_ON_ONCE(test_and_clear_bit(bit, cm->alloc_map)))
>>>     	   return;
>>>
>>> would have caught the problem at hand nicely and let the machine survive
>>> while just throwing warns and continuing is broken to begin with.
>>
>> Thanks, I like the idea. I didn't do that probably because the problem
>> which triggered me to write these patches wasn't fatal, it was just
>> causing CPU0 offlining to fail.
>
> Can you whip up a patch for that?
>

Sure, will do!

-- 
Vitaly