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Groups > linux.kernel > #1596501
| From | Daniel Borkmann <daniel@iogearbox.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf |
| Date | 2017-03-10 01:20 +0100 |
| Message-ID | <tjgrM-4b6-3@gated-at.bofh.it> (permalink) |
| References | (6 earlier) <tjepY-2Qt-3@gated-at.bofh.it> <tjezD-2W7-3@gated-at.bofh.it> <tjf2G-363-19@gated-at.bofh.it> <tjfFo-3B9-27@gated-at.bofh.it> <tjfYJ-3JY-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 03/10/2017 12:44 AM, Borislav Petkov wrote:
> On Thu, Mar 09, 2017 at 03:26:02PM -0800, Linus Torvalds wrote:
>> So should all of commit ("c109bf95992b x86/cpufeature: Remove
>> cpu_has_pge") just be reverted (and then marked for stable)?
>>
>> Or do we have some alternate plan?
>
> I think we want to do this:
>
> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
> index 6fa85944af83..fc5abff9b7fd 100644
> --- a/arch/x86/include/asm/tlbflush.h
> +++ b/arch/x86/include/asm/tlbflush.h
> @@ -188,7 +188,7 @@ static inline void __native_flush_tlb_single(unsigned long addr)
>
> static inline void __flush_tlb_all(void)
> {
> - if (static_cpu_has(X86_FEATURE_PGE))
> + if (boot_cpu_has(X86_FEATURE_PGE))
> __flush_tlb_global();
> else
> __flush_tlb();
> ---
>
> but it is late here so I'd prefer to do a real patch tomorrow when I'm
> not almost sleeping on the keyboard. Unless Daniel wants to write one
> and test it now.
I think we're in the same time zone. ;) I could send something
official tomorrow cooking a changelog with analysis, but I don't
mind at all if you want to go ahead with that either. Feel free
to add my SoB or Tested-by to it.
>> This has apparently been going on for a long while (it got merged into
>> 4.7), but presumably it only actually _matters_ if lguest is enabled
>> and used and we've triggered that lguest_arch_host_init() code.
>
> That's what I gather too, yes.
>
> What sane code would go and clear X86_FEATURE_PGE?!? :-)))
>
>> Maybe it's the lguest games with PGE that need to be removed?
>
> Well, as far as I can read the comment in lguest_arch_host_init(), it
> does some monkey business with switching to the guest kernel where
> global pages are not present anymore... or something. So it sounds to me
> like lguest would break if we removed the games but I have no idea what
> it does with that.
>
> And besides, the small hunk above restores the situation before
> ("c109bf95992b x86/cpufeature: Remove cpu_has_pge") so applying it would
> actually be a no-brainer.
Agree, looks only that hunk changed in behavior from c109bf95992b
("x86/cpufeature: Remove cpu_has_pge").
> Thanks.
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Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Fengguang Wu <fengguang.wu@intel.com> - 2017-03-02 21:30 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-02 22:40 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-08 20:30 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Kees Cook <keescook@chromium.org> - 2017-03-08 23:40 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 00:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Laura Abbott <labbott@redhat.com> - 2017-03-09 01:30 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Kees Cook <keescook@chromium.org> - 2017-03-09 06:40 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 14:10 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Thomas Gleixner <tglx@linutronix.de> - 2017-03-09 14:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 15:10 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Thomas Gleixner <tglx@linutronix.de> - 2017-03-09 16:00 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 19:00 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf David Miller <davem@davemloft.net> - 2017-03-09 19:10 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-09 19:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-09 19:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 19:40 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 22:40 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Borislav Petkov <bp@suse.de> - 2017-03-09 23:10 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 23:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Borislav Petkov <bp@suse.de> - 2017-03-09 23:50 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-10 00:30 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Borislav Petkov <bp@suse.de> - 2017-03-10 00:50 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-10 01:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Borislav Petkov <bp@suse.de> - 2017-03-12 22:50 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Borislav Petkov <bp@suse.de> - 2017-03-09 23:20 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Daniel Borkmann <daniel@iogearbox.net> - 2017-03-09 16:00 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-09 18:50 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-08 23:50 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Fengguang Wu <fengguang.wu@intel.com> - 2017-03-09 02:40 +0100
Re: [net/bpf] 3051bf36c2 BUG: unable to handle kernel paging request at 0000a7cf Thomas Gleixner <tglx@linutronix.de> - 2017-03-09 14:50 +0100
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