linux-kernel - Re: [PATCH] mm: fix up a spurious page fault whenever it happens

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <519F65DB.2020305@redhat.com>
Date:	Fri, 24 May 2013 09:06:35 -0400
From:	Rik van Riel <riel@...hat.com>
To:	Stanislav Meduna <stano@...una.org>
CC:	"H. Peter Anvin" <hpa@...or.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"linux-rt-users@...r.kernel.org" <linux-rt-users@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	the arch/x86 maintainers <x86@...nel.org>,
	Hai Huang <hhuang@...hat.com>
Subject: Re: [PATCH] mm: fix up a spurious page fault whenever it happens

On 05/24/2013 04:29 AM, Stanislav Meduna wrote:
> On 23.05.2013 14:19, Rik van Riel wrote:
>
>>>> static inline void __native_flush_tlb_single(unsigned long addr)
>>>> {
>>>>           __flush_tlb();
>>>> }
>>
>>> I will give it some more testing time.
>>
>> That is a good idea.
>
> Still no crash, so this one indeed seems to change things.
>
> If I understand it correctly, these patches fix the problem
> when it happens and we still don't know why the TLB is stale
> in the first place - whether there is (also) a genuine bug
> or whether we are hitting some chip errata, right?

Just to rule something out, are you using
transparent huge pages on those systems?

That could result in a mix of 4MB and 4kB
mappings, sometimes of the same memory.
The page tables would only ever contain
one of those mappings, but if we have some
kind of TLB problem, we might preserve a
large mapping across a page breakup, or
a small one across a page collapse...

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/