From: "Yang, Bin" <bin.yang@intel.com>
To: "tglx@linutronix.de" <tglx@linutronix.de>
Cc: "mingo@kernel.org" <mingo@kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"Gross, Mark" <mark.gross@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>
Subject: Re: [PATCH v3 5/5] x86/mm: add WARN_ON_ONCE() for wrong large page mapping
Date: Tue, 4 Sep 2018 06:32:59 +0000 [thread overview]
Message-ID: <2ad0ff43ea406005890ad4fcbb7a42da747289d9.camel@intel.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1809040023450.1462@nanos.tec.linutronix.de>
On Tue, 2018-09-04 at 00:27 +0200, Thomas Gleixner wrote:
> On Tue, 21 Aug 2018, Bin Yang wrote:
> > @@ -625,6 +625,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
> >
> > psize = page_level_size(level);
> > pmask = page_level_mask(level);
> > + addr = address & pmask;
> >
> > /*
> > * Calculate the number of pages, which fit into this large
> > @@ -636,6 +637,12 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
> > cpa->numpages = numpages;
> >
> > /*
> > + * The old pgprot should not have any protection bit. Otherwise,
> > + * the existing mapping is wrong already.
> > + */
> > + WARN_ON_ONCE(needs_static_protections(old_prot, addr, psize, old_pfn));
>
> The check itself is fine, but it just emits a warning and goes on as if
> nothing happened.
>
> We really want to think about a proper way to fix that up without overhead
> for the sane case.
could we change it as below? I think it should be safe to split large
page if current mapping is wrong already.
if (needs_static_protections(old_prot, addr, psize, old_pfn)) {
WARN_ON_ONCE(1);
goto out_unlock;
}
>
> Thanks,
>
> tglx
next prev parent reply other threads:[~2018-09-04 6:33 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 1:16 [PATCH v3 0/5] x86/mm: fix cpu stuck issue in __change_page_attr_set_clr Bin Yang
2018-08-21 1:16 ` [PATCH v3 1/5] x86/mm: avoid redundant checking if pgprot has no change Bin Yang
2018-09-03 21:57 ` Thomas Gleixner
2018-09-04 7:01 ` Yang, Bin
2018-09-04 7:49 ` Thomas Gleixner
2018-09-04 9:12 ` Yang, Bin
2018-09-04 9:22 ` Yang, Bin
2018-08-21 1:16 ` [PATCH v3 2/5] x86/mm: avoid static_protection() checking if not whole large page attr change Bin Yang
2018-08-21 1:16 ` [PATCH v3 3/5] x86/mm: add help function to check specific protection flags in range Bin Yang
2018-09-03 22:10 ` Thomas Gleixner
2018-09-04 6:22 ` Yang, Bin
2018-08-21 1:16 ` [PATCH v3 4/5] x86/mm: optimize static_protection() by using overlap() Bin Yang
2018-09-04 12:22 ` Thomas Gleixner
2018-09-07 1:14 ` Yang, Bin
2018-09-07 7:49 ` Thomas Gleixner
2018-09-07 8:04 ` Yang, Bin
2018-09-07 8:21 ` Thomas Gleixner
2018-09-07 8:26 ` Yang, Bin
2018-08-21 1:16 ` [PATCH v3 5/5] x86/mm: add WARN_ON_ONCE() for wrong large page mapping Bin Yang
2018-09-03 22:27 ` Thomas Gleixner
2018-09-04 6:32 ` Yang, Bin [this message]
2018-09-04 7:41 ` Thomas Gleixner
2018-09-04 16:52 ` Thomas Gleixner
2018-09-07 2:12 ` Yang, Bin
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