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From: Michael Ellerman <mpe@ellerman•id.au>
To: Abdul Haleem <abdhalee@linux•vnet.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@lists•ozlabs.org>,
	linux-kernel <linux-kernel@vger•kernel.org>,
	linux-next <linux-next@vger•kernel.org>,
	Stephen Rothwell <sfr@canb•auug.org.au>,
	Rob Herring <robh@kernel•org>, Paul Mackerras <paulus@samba•org>
Subject: Re: [DLPAR CPU][Oops] Bad kernel stack pointer
Date: Fri, 22 Sep 2017 22:26:10 +1000	[thread overview]
Message-ID: <87poaiudgd.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <1506074224.17232.8.camel@abdul.in.ibm.com>

Abdul Haleem <abdhalee@linux•vnet.ibm.com> writes:

> On Wed, 2017-09-20 at 21:42 +1000, Michael Ellerman wrote:
>> Abdul Haleem <abdhalee@linux•vnet.ibm.com> writes:
>> 
>> > Hi,
>> >
>> > Dynamic CPU remove operation resulted in Kernel Panic on today's
>> > next-20170915 kernel.
>> >
>> > Machine Type: Power 7 PowerVM LPAR
>> > Kernel : 4.13.0-next-20170915
>> > config : attached
>> > test: DLPAR CPU remove
>> >
>> >
>> > dmesg logs:
>> > ----------
>> > cpu 37 (hwid 37) Ready to die...
>> > cpu 38 (hwid 38) Ready to die...
>> > cpu 39 (hwid 39)
>> > ******* RTAS CReady to die...
>> > ALL BUFFER CORRUPTION *******
>> 
>> Cool. Does that come from RTAS itself? I have never seen that happen
>> before.
>
> Not sure, the var logs does not have any messages captured. This is
> first time we hit this type of issue.

Yeah it is from RTAS:

# lsprop /proc/device-tree/rtas/linux,rtas-base 
/proc/device-tree/rtas/linux,rtas-base
		 1eca0000 (516554752)
# lsprop /proc/device-tree/rtas/rtas-size
/proc/device-tree/rtas/rtas-size
		 01360000 (20316160)

# dd if=/dev/mem bs=4096 skip=126112 count=4960 of=rtas.bin
# strings rtas.bin | grep "RTAS CALL BUFFER"
******* RTAS CALL BUFFER CORRUPTION *******


So we were doing an RTAS call and RTAS itself detected that the call
buffer was corrupted. I'm not sure how it detects that, but something is
definitely screwed up.

>> Is this easily reproducible?
>
> I am unable to reproduce it again. I will keep an eye on our CI runs for
> few more runs.

OK thanks.

cheers

  reply	other threads:[~2017-09-22 12:26 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-18 10:08 [linux-next][DLPAR CPU][Oops] Bad kernel stack pointer Abdul Haleem
2017-09-18 12:44 ` [DLPAR " Rob Herring
2017-09-19 13:34   ` Abdul Haleem
2017-09-20 11:42 ` Michael Ellerman
2017-09-22  9:57   ` Abdul Haleem
2017-09-22 12:26     ` Michael Ellerman [this message]
2017-09-22 12:38     ` Abdul Haleem

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