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Date:   Wed, 6 Jan 2021 20:49:14 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Willem de Bruijn <willemb@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        David Miller <davem@davemloft.net>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Matthew Wilcox <willy@infradead.org>,
        Daniel Vetter <daniel@ffwll.ch>,
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        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Netdev <netdev@vger.kernel.org>
Subject: Re: [BUG] from x86: Support kmap_local() forced debugging
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On Wed, 6 Jan 2021 17:03:48 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -366,7 +366,7 @@ static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
>  static inline bool skb_frag_must_loop(struct page *p)
>  {
>  #if defined(CONFIG_HIGHMEM)
> -	if (PageHighMem(p))
> +	if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) || PageHighMem(p))
>  		return true;
>  #endif
>  	return false;

I applied this and I haven't been able to crash it again.

Thanks,

-- Steve