From: "Luck, Tony" <tony.luck@intel.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-edac <linux-edac@vger.kernel.org>, X86 ML <x86@kernel.org>,
DanWilliamsdan.j.williams@intel.com
Subject: Re: [PATCH 1/3] x86, ras: Add new infrastructure for machine check fixup tables
Date: Thu, 12 Nov 2015 13:17:41 -0800 [thread overview]
Message-ID: <20151112211741.GA503@agluck-desk.sc.intel.com> (raw)
In-Reply-To: <CALCETrV-bXgMPOkjvEuBwyCAU-cS5aw3i54wGQ7w9cwqfLt1tg@mail.gmail.com>
On Thu, Nov 12, 2015 at 12:04:36PM -0800, Andy Lutomirski wrote:
> > We already have code to recover from machine checks encountered
> > while the processor is executing ring3 code.
>
> I meant failures during copy_from_user, copy_to_user, etc.
Yes. copy_from_user() will be pretty interesting from a coverage point
of view. We can recover by sending a SIGBUS to the process just like
we would have if the process had accessed the data directly rather than
passing the address to the kernel to acccess it.
copy_to_user() is a lot harder. The machine check is on the kernel side
of the copy. If we are copying from page cache as part of a read(2)
syscall from a regular file we can probably nuke the page from the cache
and return -EIO to the user. Other cases may be possible, but I don't
immediately see any way to do it as a general case.
-Tony
next prev parent reply other threads:[~2015-11-12 21:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-09 18:26 [RFC PATCH 0/3] Machine check recovery when kernel accesses poison Tony Luck
2015-11-06 20:57 ` [PATCH 1/3] x86, ras: Add new infrastructure for machine check fixup tables Tony Luck
2015-11-10 11:21 ` Borislav Petkov
2015-11-10 22:05 ` Luck, Tony
2015-11-12 4:14 ` Andy Lutomirski
2015-11-12 19:44 ` Luck, Tony
2015-11-12 20:04 ` Andy Lutomirski
2015-11-12 21:17 ` Luck, Tony [this message]
2015-11-06 21:01 ` [PATCH 2/3] x86, ras: Extend machine check recovery code to annotated ring0 areas Tony Luck
2015-11-10 11:21 ` Borislav Petkov
2015-11-10 22:11 ` Luck, Tony
2015-11-11 11:01 ` Borislav Petkov
2015-11-12 4:19 ` Andy Lutomirski
2015-11-12 19:55 ` Luck, Tony
2015-11-06 21:08 ` [PATCH 3/3] x86, ras: Add mcsafe_memcpy() function to recover from machine checks Tony Luck
2015-11-12 7:53 ` Ingo Molnar
2015-11-12 20:01 ` Luck, Tony
2015-11-27 10:16 ` Ingo Molnar
2015-12-08 21:30 ` Dan Williams
2015-12-08 22:08 ` Luck, Tony
2015-12-08 22:08 ` Luck, Tony
2015-12-14 9:55 ` Ingo Molnar
2015-11-09 18:48 ` [RFC PATCH 0/3] Machine check recovery when kernel accesses poison Tony Luck
2015-11-10 11:21 ` Borislav Petkov
2015-11-10 21:55 ` Luck, Tony
2015-11-11 20:41 ` Borislav Petkov
2015-11-11 21:48 ` Luck, Tony
2015-11-11 22:28 ` Borislav Petkov
2015-11-11 22:32 ` Luck, Tony
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