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From: Aili Yao <yaoaili@kingsoft.com>
To: "HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
	"Luck, Tony" <tony.luck@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>,
	"david@redhat.com" <david@redhat.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"yangfeng1@kingsoft.com" <yangfeng1@kingsoft.com>,
	"sunhao2@kingsoft.com" <sunhao2@kingsoft.com>,
	<yaoaili@kingsoft.com>
Subject: Re: [PATCH v3] mm,hwpoison: return -EHWPOISON when page already poisoned
Date: Tue, 6 Apr 2021 09:04:44 +0800	[thread overview]
Message-ID: <20210406090444.2a69b9e2@alex-virtual-machine> (raw)
In-Reply-To: <20210405135017.GA6504@hori.linux.bs1.fc.nec.co.jp>

On Mon, 5 Apr 2021 13:50:18 +0000
HORIGUCHI NAOYA(堀口 直也) <naoya.horiguchi@nec.com> wrote:

> On Fri, Apr 02, 2021 at 03:11:20PM +0000, Luck, Tony wrote:
> > >> Combined with my "mutex" patch (to get rid of races where 2nd process returns
> > >> early, but first process is still looking for mappings to unmap and tasks
> > >> to signal) this patch moves forward a bit. But I think it needs an
> > >> additional change here in kill_me_maybe() to just "return" if there is a
> > >> EHWPOISON return from memory_failure()
> > >> 
> > > Got this, Thanks for your reply!
> > > I will dig into this!
> > 
> > One problem with this approach is when the first task to find poison
> > fails to complete actions. Then the poison pages are not unmapped,
> > and just returning from kill_me_maybe() gets into a loop :-(
> 
> Yes, that's the pain point.  We need send SIGBUS to the current process in
> "already haredware poisoned" case of memory_failure().  SIGBUS should
> contain the error virtual address, but unfortunately walking the page table
> or using p->mce_vaddr is not always reliable now.
> 
> So as a second-best approach, we can extend the "walking page table"
> approach such that we walk over the whole virtual address space to make sure
> that the number of entries pointing to the error page is exactly 1.
> If that's the case, then we can confidently send SIGBUS with it.  If we find
> multiple entries pointing to the error page, then we give up guessing, then
> send a nomral SIGBUS to the current process.  That's not worse than now,
> and I think we need wait in the hope that the virtual address will be
> available in MCE handler.
> 
> Anyway I'll try to write a patch for this.

Yeah, previous patch didn't adress the multiple virtual address issue, If there is a way to fix that,
That would be great!

-- 
Thanks!
Aili Yao

  reply	other threads:[~2021-04-06  1:04 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-24  7:16 [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Aili Yao
2021-02-24 10:10 ` David Hildenbrand
2021-02-24 10:31 ` Oscar Salvador
2021-02-25  3:43   ` Aili Yao
2021-02-25 11:28     ` HORIGUCHI NAOYA(堀口 直也)
2021-02-25 11:39       ` Oscar Salvador
2021-02-25 12:38         ` HORIGUCHI NAOYA(堀口 直也)
2021-02-25 18:15           ` Luck, Tony
2021-02-26  2:19             ` HORIGUCHI NAOYA(堀口 直也)
2021-02-26  2:59               ` Aili Yao
2021-03-03  3:39                 ` Luck, Tony
2021-03-03  3:57                   ` Aili Yao
2021-03-03  8:39                     ` Aili Yao
2021-03-03 15:41                       ` Luck, Tony
2021-03-04  2:16                         ` Aili Yao
2021-03-04  4:19                           ` Aili Yao
2021-03-04  6:45                             ` Aili Yao
2021-03-04 23:57                               ` Luck, Tony
2021-03-05  1:30                                 ` Aili Yao
2021-03-05  1:36                                   ` Aili Yao
2021-03-05 22:11                                     ` Luck, Tony
2021-03-08  6:45                                       ` HORIGUCHI NAOYA(堀口 直也)
2021-03-08 18:54                                         ` Luck, Tony
2021-03-08 22:38                                           ` HORIGUCHI NAOYA(堀口 直也)
2021-03-08 22:55                                             ` [PATCH] mm/memory-failure: Use a mutex to avoid memory_failure() races Luck, Tony
2021-03-08 23:42                                               ` HORIGUCHI NAOYA(堀口 直也)
2021-03-09  2:04                                               ` Aili Yao
2021-03-09  6:04                                                 ` HORIGUCHI NAOYA(堀口 直也)
2021-03-09  6:35                                                   ` [PATCH v2] mm,hwpoison: return -EBUSY when page already poisoned Aili Yao
2021-03-09  8:28                                                     ` HORIGUCHI NAOYA(堀口 直也)
2021-03-09 20:01                                                       ` Luck, Tony
2021-03-10  8:05                                                         ` HORIGUCHI NAOYA(堀口 直也)
2021-03-13  1:55                                                         ` Jue Wang
2021-03-13  1:55                                                           ` Jue Wang
2021-03-10  8:01                                                       ` Aili Yao
2021-03-31 11:25                                                     ` [PATCH v3] mm,hwpoison: return -EHWPOISON " Aili Yao
2021-04-01 15:33                                                       ` Luck, Tony
2021-04-02  1:18                                                         ` Aili Yao
2021-04-02 15:11                                                           ` Luck, Tony
2021-04-05 13:50                                                             ` HORIGUCHI NAOYA(堀口 直也)
2021-04-06  1:04                                                               ` Aili Yao [this message]
2021-03-09  6:38                                                   ` [PATCH] mm/memory-failure: Use a mutex to avoid memory_failure() races Aili Yao
2021-03-05 15:55                                   ` [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Luck, Tony
2021-03-10  6:10                                     ` Aili Yao
2021-03-11  8:55                                       ` HORIGUCHI NAOYA(堀口 直也)
2021-03-11 11:23                                         ` Aili Yao
2021-03-11 17:05                                         ` Luck, Tony
2021-03-12  5:55                                           ` Aili Yao
2021-03-12 16:29                                             ` Luck, Tony
2021-03-12 23:48                                               ` Luck, Tony
2021-03-16  6:42                                                 ` HORIGUCHI NAOYA(堀口 直也)
2021-03-16  7:54                                                   ` Aili Yao
2021-03-17  0:29                                                 ` Luck, Tony
2021-03-17  9:07                                                   ` Aili Yao
2021-03-17  7:48                                         ` Aili Yao
2021-03-17  8:23                                           ` Aili Yao
2021-02-26  3:26               ` Tony Luck
2021-02-26  3:26                 ` Tony Luck
2021-02-26  2:52         ` Aili Yao
2021-02-26 17:58           ` Luck, Tony
2021-03-02  4:32             ` Aili Yao
2021-03-31 10:56         ` Aili Yao
2021-03-31 10:58           ` David Hildenbrand

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