From: "Luck, Tony" <tony.luck@intel.com>
To: Aili Yao <yaoaili@kingsoft.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>,
"bp@alien8.de" <bp@alien8.de>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.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>
Subject: RE: [PATCH] mm,hwpoison: return -EBUSY when page already poisoned
Date: Fri, 12 Mar 2021 23:48:31 +0000 [thread overview]
Message-ID: <af80221baed940d8bcc643e3e7d40036@intel.com> (raw)
In-Reply-To: <3900f518d1324c388be52cf81f5220e4@intel.com>
>> will memory_failure() find it and unmap it? if succeed, then the current will be
>> signaled with correct vaddr and shift?
>
> That's a very good question. I didn't see a SIGBUS when I first wrote this code,
> hence all the p->mce_vaddr. But now I'm
> a) not sure why there wasn't a signal
> b) if we are to fix the problems noted by AndyL, need to make sure that there isn't a SIGBUS
Tests on upstream kernel today show that memory_failure() is both unmapping the page
and sending a SIGBUS.
My biggest issue with the KERNEL_COPYIN recovery path is that we don't have code
to mark the page not present while we are still in do_machine_check(). That's resulted
in recovery working for simple cases where there is a single get_user() call followed by
an error return if that failed. But more complex cases require more machine checks and
a touching faith that the kernel will eventually give up trying (spoiler: it sometimes doesn't).
Thanks to the decode of the instruction we do have the virtual address. So we just need
a safe walk of pgd->p4d->pud->pmd->pte (truncated if we hit a huge page) with a write
of a "not-present" value. Maybe a different poison type from the one we get from
memory_failure() so that the #PF code can recognize this as a special case and do any
other work that we avoided because we were in #MC context.
-Tony
next prev parent reply other threads:[~2021-03-12 23:49 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210224151619.67c29731@alex-virtual-machine>
[not found] ` <20210224103105.GA16368@linux>
[not found] ` <20210225114329.4e1a41c6@alex-virtual-machine>
[not found] ` <20210225112818.GA10141@hori.linux.bs1.fc.nec.co.jp>
[not found] ` <20210225113930.GA7227@localhost.localdomain>
[not found] ` <20210225123806.GA15006@hori.linux.bs1.fc.nec.co.jp>
[not found] ` <20210225181542.GA178925@agluck-desk2.amr.corp.intel.com>
[not found] ` <20210226021907.GA27861@hori.linux.bs1.fc.nec.co.jp>
2021-02-26 2:59 ` [PATCH] mm,hwpoison: return -EBUSY when page already poisoned 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
2021-03-10 8:01 ` 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 [this message]
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
[not found] ` <20210226105250.3a15e35c@alex-virtual-machine>
2021-02-26 17:58 ` Luck, Tony
2021-03-02 4:32 ` Aili Yao
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