linux-kernel - Re: 3.10.9: kmemleak disables all CPUs except CPU0

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Date:	Mon, 02 Sep 2013 17:46:06 +0200
From:	Martin MOKREJŠ <mmokrejs@...il.com>
To:	Catalin Marinas <catalin.marinas@....com>
CC:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: 3.10.9: kmemleak disables all CPUs except CPU0



Catalin Marinas wrote:
> On 31 August 2013 14:35, Martin MOKREJŠ <mmokrejs@...il.com> wrote:
>>   never realized that my CPUs are gone if I compile into kernel kmemleak.
>> Is that really the aim?
>>
>> CONFIG_HAVE_DEBUG_KMEMLEAK=y
>> CONFIG_DEBUG_KMEMLEAK=y
>> CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=400
>> # CONFIG_DEBUG_KMEMLEAK_TEST is not set
>> # CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF is not set
>>
>> 1.  Why isn't there /sys/devices/system/cpu/cpu0/online file?
>> Does not matter if it contains 0 or 1. It just should exist.
> 
> I can't really see how kmemleak would do this, maybe other config
> options that get set/cleared in the process of selecting kmemleak. Can
> you do a diff between your config with /sys/... entries and the one
> without?

Hi,
  I tried but did not get to report back. One one these re-enabled my CPUs back.

@@ -3177,14 +3179,7 @@
 CONFIG_HAVE_ARCH_KGDB=y
 # CONFIG_KGDB is not set
 CONFIG_HAVE_ARCH_KMEMCHECK=y
-CONFIG_KMEMCHECK=y
-# CONFIG_KMEMCHECK_DISABLED_BY_DEFAULT is not set
-# CONFIG_KMEMCHECK_ENABLED_BY_DEFAULT is not set
-CONFIG_KMEMCHECK_ONESHOT_BY_DEFAULT=y
-CONFIG_KMEMCHECK_QUEUE_SIZE=64
-CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT=5
-CONFIG_KMEMCHECK_PARTIAL_OK=y
-# CONFIG_KMEMCHECK_BITOPS_OK is not set
+# CONFIG_KMEMCHECK is not set
 # CONFIG_TEST_STRING_HELPERS is not set
 # CONFIG_TEST_KSTRTOX is not set
 # CONFIG_STRICT_DEVMEM is not set


So, the CONFIG_KMEMCHECK disables the additional CPUs I believe. I thought it
should be traceable from the dmesg output I sent to the list. Yes, I screwed the
subject line because I did not realize a difference so far. :(

Martin
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