From: Aili Yao <yaoaili@kingsoft.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: "HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
"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, yaoaili@kingsoft.com
Subject: Re: [PATCH v3] mm,hwpoison: return -EHWPOISON when page already poisoned
Date: Fri, 2 Apr 2021 09:18:20 +0800 [thread overview]
Message-ID: <20210402091820.04d7c3e0@alex-virtual-machine> (raw)
In-Reply-To: <20210401153320.GA426964@agluck-desk2.amr.corp.intel.com>
On Thu, 1 Apr 2021 08:33:20 -0700
"Luck, Tony" <tony.luck@intel.com> wrote:
> On Wed, Mar 31, 2021 at 07:25:40PM +0800, Aili Yao wrote:
> > When the page is already poisoned, another memory_failure() call in the
> > same page now return 0, meaning OK. For nested memory mce handling, this
> > behavior may lead to one mce looping, Example:
> >
> > 1.When LCME is enabled, and there are two processes A && B running on
> > different core X && Y separately, which will access one same page, then
> > the page corrupted when process A access it, a MCE will be rasied to
> > core X and the error process is just underway.
> >
> > 2.Then B access the page and trigger another MCE to core Y, it will also
> > do error process, it will see TestSetPageHWPoison be true, and 0 is
> > returned.
> >
> > 3.The kill_me_maybe will check the return:
> >
> > 1244 static void kill_me_maybe(struct callback_head *cb)
> > 1245 {
> >
> > 1254 if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags) &&
> > 1255 !(p->mce_kflags & MCE_IN_KERNEL_COPYIN)) {
> > 1256 set_mce_nospec(p->mce_addr >> PAGE_SHIFT,
> > p->mce_whole_page);
> > 1257 sync_core();
> > 1258 return;
> > 1259 }
> >
> > 1267 }
>
> With your change memory_failure() will return -EHWPOISON for the
> second task that consumes poison ... so that "if" statement won't
> be true and so we fall into the following code:
>
> 1273 if (p->mce_vaddr != (void __user *)-1l) {
> 1274 force_sig_mceerr(BUS_MCEERR_AR, p->mce_vaddr, PAGE_SHIFT);
> 1275 } else {
> 1276 pr_err("Memory error not recovered");
> 1277 kill_me_now(cb);
> 1278 }
>
> If this was a copy_from_user() machine check, p->mce_vaddr is set and
> the task gets a BUS_MCEERR_AR SIGBUS, otherwise we print that
>
> "Memory error not recovered"
>
> message and send a generic SIGBUS. I don't think either of those options
> is right.
>
> 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!
--
Thanks!
Aili Yao
next prev parent reply other threads:[~2021-04-02 1:18 UTC|newest]
Thread overview: 60+ 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)
[not found] ` <20210309100421.3d09b6b1@alex-virtual-machine>
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
2021-03-10 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 [this message]
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
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 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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