Date: Thu, 9 Mar 2017 14:10:46 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Daniel Borkmann <daniel@iogearbox.net>
cc: Kees Cook <keescook@chromium.org>, Laura Abbott <labbott@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>, Peter Anvin <hpa@zytor.com>,
        Fengguang Wu <fengguang.wu@intel.com>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, LKP <lkp@01.org>, ast@fb.com,
        the arch/x86 maintainers <x86@kernel.org>,
        "David S. Miller" <davem@davemloft.net>
Subject: Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request
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On Thu, 9 Mar 2017, Daniel Borkmann wrote:
> With regard to CPA_FLUSHTLB that Linus mentioned, when I investigated
> code paths in change_page_attr_set_clr(), I did see that CPA_FLUSHTLB
> was set each time we switched attrs and a cpa_flush_range() was
> performed (with the correct number of pages and cache set to 0). That
> would be a __flush_tlb_all() eventually.
> 
> Hmm, it indeed might seem likely that this could be an emulation bug.

Which variant of __flush_tlb_all() is used when the test fails?

Check for the following flags in /proc/cpuinfo: pge invpcid

Thanks,

	tglx