From: Meelis Roos <mroos@linux.ee>
To: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Joonsoo Kim <js1304@gmail.com>,
Peter Hurley <peter@hurleysoftware.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
David Miller <davem@davemloft.net>,
sparclinux@vger.kernel.org
Subject: Re: Slab BUG with DEBUG_* options
Date: Sun, 8 Dec 2013 17:00:16 +0200 (EET) [thread overview]
Message-ID: <alpine.SOC.1.00.1312040005350.25191@math.ut.ee> (raw)
In-Reply-To: <00000142ba77e59d-3e002746-996d-4843-b8f1-51d1431b47a9-000000@email.amazonses.com>
(Added 3 addresses to CC from my RED state exception thread since this
is related)
> On Tue, 3 Dec 2013, Meelis Roos wrote:
>
> > Tested it. seems to hang after switching to another console. Before
> > that, slabs are initialized successfully, I verified it with my previous
> > debug printk sprinkle patch. Many allocations are still off slab - is
> > that OK?
>
> Yes that was the intend. Only exempt the small ones.
>
> > console [tty0] enabled, bootconsole disabled
>
> Looks like the bootstrap worked.
But the configuration should work fine with this console setup - with no
slab debug options, it booted fine... I decided to do more tests.
In short, tests about 3.11-rc2-00058:
clean kernel: boots OK, RED state on shutdown (the actual problem I am
chasing)
clean kernel, slab debug: mm crash
your second slab patch, slab debug: OK - this one shows that the RED
state problem went away too which is good but strange
clean kernel, your second slab patch: OK - no RED state
Following another lead I had discovered that I can make the RED state
problem go away if I switch tty ldata allocation from vmalloc to
kmalloc. Tests with that:
ldata alloc change only, no slab debug: OK (works around RED state
somehow)
ldata alloc change + slab debug: mm crash, can not test for RED state
ldata alloc change + your second slab patch + slab debug: hang on boot
after
console [tty0] enabled, bootconsole disabled
(after that, I should see all the dmesg again on serial but I do not).
ldata alloc change + your second slab patch + no slab debug: OK
So, in short:
your slab patch 2 seems to cure both slab debug startup crash and the
RED state problem in this specific version of the kernel. However, it is
still mystery to me why tty ldata alloc change vmalloc->kmalloc would
break but that may to be in the serial field - will do more tests with
this patch applied and newer kernels.
--
Meelis Roos (mroos@linux.ee)
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prev parent reply other threads:[~2013-12-08 15:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-30 11:42 Meelis Roos
2013-11-30 22:31 ` David Rientjes
2013-12-02 19:02 ` Christoph Lameter
2013-12-03 8:46 ` Meelis Roos
2013-12-03 9:17 ` Meelis Roos
2013-12-03 11:53 ` Pekka Enberg
2013-12-03 12:25 ` Joonsoo Kim
2013-12-03 12:44 ` Pekka Enberg
2013-12-03 15:46 ` Christoph Lameter
2013-12-03 20:33 ` Meelis Roos
2013-12-03 20:59 ` Christoph Lameter
[not found] ` <alpine.DEB.2.02.1312030930450.4115@gentwo.org>
2013-12-03 20:25 ` Christoph Lameter
2013-12-03 21:18 ` Meelis Roos
2013-12-03 21:58 ` Christoph Lameter
2013-12-08 15:00 ` Meelis Roos [this message]
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