linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Andy Lutomirski <luto@amacapital.net>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>,
	Aili Yao <yaoaili@kingsoft.com>,
	HORIGUCHI NAOYA <naoya.horiguchi@nec.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
	yangfeng1@kingsoft.com, Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] x86/fault: Send a SIGBUS to user process always for hwpoison page access.
Date: Mon, 1 Mar 2021 11:09:36 -0800	[thread overview]
Message-ID: <59469ECC-5316-4074-98EF-52FFF7940818@amacapital.net> (raw)
In-Reply-To: <8d0c76f97f35499f91a2b82d3e7c024d@intel.com>



> On Mar 1, 2021, at 11:02 AM, Luck, Tony <tony.luck@intel.com> wrote:
> 
> 
>> 
>> Some programs may use read(2), write(2), etc as ways to check if
>> memory is valid without getting a signal.  They might not want
>> signals, which means that this feature might need to be configurable.
> 
> That sounds like an appalling hack. If users need such a mechanism
> we should create some better way to do that.
> 

Appalling hack or not, it works. So, if we’re going to send a signal to user code that looks like it originated from a bina fide architectural recoverable fault, it needs to be recoverable.  A load from a failed NVDIMM page is such a fault. A *kernel* load is not. So we need to distinguish it somehow.

> An aeon ago ACPI created the RASF table as a way for the OS to
> ask the platform to scan a block of physical memory using the patrol
> scrubber in the memory controller.  I never did anything with it in Linux
> because it was just too complex and didn't know of any use cases.
> 
> Users would want to check virtual addresses. Perhaps some new
> option MADV_CHECKFORPOISON to madvise(2) ?
> 
> -Tony


  reply	other threads:[~2021-03-01 19:09 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-01  8:17 [PATCH v2] x86/fault: Send a SIGBUS to user process always for hwpoison page access Aili Yao
2021-02-01 16:58 ` Andy Lutomirski
2021-02-01 21:10   ` Luck, Tony
2021-02-01 22:09     ` Andy Lutomirski
2021-02-02  6:42   ` Aili Yao
2021-02-04  7:25 ` HORIGUCHI NAOYA(堀口　直也)
2021-02-05  5:06   ` Aili Yao
2021-02-05  9:01   ` [PATCH v3] " Aili Yao
2021-02-23 12:44     ` Aili Yao
2021-02-23 15:33       ` Andy Lutomirski
2021-02-23 16:42         ` Luck, Tony
2021-02-25  4:47           ` Aili Yao
2021-02-27  3:40             ` Andy Lutomirski
2021-03-01  7:57               ` Aili Yao
2021-03-01 18:12                 ` Luck, Tony
2021-03-01 19:02               ` Luck, Tony
2021-03-01 19:09                 ` Andy Lutomirski [this message]
2021-03-03 12:24                   ` Aili Yao
2021-03-03 12:51                     ` Aili Yao
2021-03-07 19:16                       ` Andy Lutomirski
2021-03-08  9:49                         ` Aili Yao
2021-03-08 18:14                           ` Andy Lutomirski
2021-03-08 18:31                             ` Luck, Tony
2021-03-08 19:00                               ` Andy Lutomirski
2021-03-11  1:19                                 ` Aili Yao
2021-03-11  1:28                                   ` Andy Lutomirski
2021-03-11  2:01                                     ` Aili Yao
2021-03-11 16:52                                     ` Luck, Tony
2021-03-11 16:56                                       ` Peter Zijlstra
2021-03-09  2:14                               ` Aili Yao
2021-03-09  2:25                                 ` Aili Yao

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=59469ECC-5316-4074-98EF-52FFF7940818@amacapital.net \
    --to=luto@amacapital.net \
    --cc=bp@alien8.de \
    --cc=dave.hansen@linux.intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=naoya.horiguchi@nec.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=tony.luck@intel.com \
    --cc=x86@kernel.org \
    --cc=yangfeng1@kingsoft.com \
    --cc=yaoaili@kingsoft.com \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).