From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Tony Luck <tony.luck@intel.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Peter Zijlstra <peterz@infradead.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Al Viro <viro@zeniv.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/6] use memcpy_mcsafe() for copy_to_iter()
Date: Wed, 02 May 2018 03:13:31 +0000 [thread overview]
Message-ID: <CA+55aFzDt1uvDBqgkB0T2o2-d5Fi0tBiGcy5iAZ-wRNdAL4uQw@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4jTUn2gSPSB1r7p9A7VNxBf54Aa5dnGbGsomDqmbvsHLQ@mail.gmail.com>
On Tue, May 1, 2018 at 8:03 PM Dan Williams <dan.j.williams@intel.com>
wrote:
> Because dax. There's no page cache indirection games we can play here
> to poison a page and map in another page. The mapped page is 1:1
> associated with the filesystem block and physical memory address.
I'm not talking page cache indirection.
I'm talking literally mapping a different page into the kernel virtual
address space that the failing read was done for.
But you seem to be right that we don't actually support that. I'm guessing
the hwpoison code has never had to run in that kind of situation and will
just give up.
That would seem to be sad. It really feels like the obvious solution to any
MCE's - just map a dummy page at the address that causes problems.
That can have bad effects for real memory (because who knows what internal
kernel data structure might be in there), but would seem to be the
_optimal_ solution for some random pmem access. And makes it absolutely
trivial to just return to the execution that got the error exception.
Linus
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Tony Luck <tony.luck@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>,
"the arch/x86 maintainers" <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/6] use memcpy_mcsafe() for copy_to_iter()
Date: Wed, 02 May 2018 03:13:31 +0000 [thread overview]
Message-ID: <CA+55aFzDt1uvDBqgkB0T2o2-d5Fi0tBiGcy5iAZ-wRNdAL4uQw@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4jTUn2gSPSB1r7p9A7VNxBf54Aa5dnGbGsomDqmbvsHLQ@mail.gmail.com>
On Tue, May 1, 2018 at 8:03 PM Dan Williams <dan.j.williams@intel.com>
wrote:
> Because dax. There's no page cache indirection games we can play here
> to poison a page and map in another page. The mapped page is 1:1
> associated with the filesystem block and physical memory address.
I'm not talking page cache indirection.
I'm talking literally mapping a different page into the kernel virtual
address space that the failing read was done for.
But you seem to be right that we don't actually support that. I'm guessing
the hwpoison code has never had to run in that kind of situation and will
just give up.
That would seem to be sad. It really feels like the obvious solution to any
MCE's - just map a dummy page at the address that causes problems.
That can have bad effects for real memory (because who knows what internal
kernel data structure might be in there), but would seem to be the
_optimal_ solution for some random pmem access. And makes it absolutely
trivial to just return to the execution that got the error exception.
Linus
next prev parent reply other threads:[~2018-05-02 3:13 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-01 20:45 [PATCH 0/6] use memcpy_mcsafe() for copy_to_iter() Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 20:45 ` [PATCH 1/6] x86, memcpy_mcsafe: update labels in support of write fault handling Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 20:45 ` [PATCH 2/6] x86, memcpy_mcsafe: return bytes remaining Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 20:45 ` [PATCH 3/6] x86, memcpy_mcsafe: add write-protection-fault handling Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 20:45 ` [PATCH 4/6] x86, memcpy_mcsafe: define copy_to_iter_mcsafe() Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 22:17 ` kbuild test robot
2018-05-01 22:17 ` kbuild test robot
2018-05-01 22:49 ` kbuild test robot
2018-05-01 22:49 ` kbuild test robot
2018-05-01 20:45 ` [PATCH 5/6] dax: use copy_to_iter_mcsafe() in dax_iomap_actor() Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 20:45 ` [PATCH 6/6] x86, nfit_test: unit test for memcpy_mcsafe() Dan Williams
2018-05-01 20:45 ` Dan Williams
2018-05-01 21:05 ` [PATCH 0/6] use memcpy_mcsafe() for copy_to_iter() Linus Torvalds
2018-05-01 21:05 ` Linus Torvalds
2018-05-01 23:02 ` Dan Williams
2018-05-01 23:02 ` Dan Williams
2018-05-01 23:28 ` Andy Lutomirski
2018-05-01 23:28 ` Andy Lutomirski
2018-05-01 23:31 ` Dan Williams
2018-05-01 23:31 ` Dan Williams
2018-05-02 0:09 ` Linus Torvalds
2018-05-02 0:09 ` Linus Torvalds
2018-05-02 2:25 ` Dan Williams
2018-05-02 2:25 ` Dan Williams
2018-05-02 2:53 ` Linus Torvalds
2018-05-02 2:53 ` Linus Torvalds
2018-05-02 3:02 ` Dan Williams
2018-05-02 3:02 ` Dan Williams
2018-05-02 3:13 ` Linus Torvalds [this message]
2018-05-02 3:13 ` Linus Torvalds
2018-05-02 3:20 ` Dan Williams
2018-05-02 3:20 ` Dan Williams
2018-05-02 3:22 ` Dan Williams
2018-05-02 3:22 ` Dan Williams
2018-05-02 3:33 ` Linus Torvalds
2018-05-02 3:33 ` Linus Torvalds
2018-05-02 4:00 ` Dan Williams
2018-05-02 4:00 ` Dan Williams
2018-05-02 4:14 ` Linus Torvalds
2018-05-02 4:14 ` Linus Torvalds
2018-05-02 5:37 ` Dan Williams
2018-05-02 5:37 ` Dan Williams
2018-05-02 16:19 ` Andy Lutomirski
2018-05-02 16:19 ` Andy Lutomirski
2018-05-02 17:47 ` Dan Williams
2018-05-02 17:47 ` Dan Williams
2018-05-02 8:30 ` Borislav Petkov
2018-05-02 8:30 ` Borislav Petkov
2018-05-02 13:52 ` Dan Williams
2018-05-02 13:52 ` Dan Williams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CA+55aFzDt1uvDBqgkB0T2o2-d5Fi0tBiGcy5iAZ-wRNdAL4uQw@mail.gmail.com \
--to=torvalds@linux-foundation.org \
--cc=akpm@linux-foundation.org \
--cc=bp@alien8.de \
--cc=dan.j.williams@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@lists.01.org \
--cc=luto@amacapital.net \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=viro@zeniv.linux.org.uk \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.