linux-kernel - Re: kmemleak, cpu usage jump out of nowhere

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Date:	Wed, 14 Jul 2010 10:27:57 +0200
From:	Zeno Davatz <zdavatz@...il.com>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	linux-kernel@...r.kernel.org,
	Catalin Marinas <catalin.marinas@....com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: kmemleak, cpu usage jump out of nowhere

Dear Pekka

On Wed, Jul 14, 2010 at 10:05 AM, Pekka Enberg <penberg@...helsinki.fi> wrote:
> On Wed, Jul 14, 2010 at 9:12 AM, Zeno Davatz <zdavatz@...il.com> wrote:
>> I got a new Intel core-8 i7 processor.
>>
>> I am on kernel uname -a
>>
>> Linux zenogentoo 2.6.35-rc5 #97 SMP Tue Jul 13 16:13:25 CEST 2010 i686
>> Intel(R) Core(TM) i7 CPU 960 @ 3.20GHz GenuineIntel GNU/Linux
>>
>> Sometimes in the middle of nowhere all of a sudden all of my 8-cores
>> are at 100% CPU usage and my machine really lags and hangs and is not
>> useable anymore. Some random process just grabs a bunch CPUs according
>> to htop.
>
> Why did you enable CONFIG_DEBUG_KMEMLEAK? Memory leak scanning is
> likely the source of these pauses.

Shall I disable that? I will do that and try again.

>> I am attaching you the file from /sys/kernel/debug/kmemleak
>
> Zeno, can you post your dmesg and .config, please?

Sure, see attached files.

> The third class of leaks is relateed to drm_setversion():
>
> unreferenced object 0xf6b10620 (size 32):
>  comm "X", pid 2268, jiffies 4294894722 (age 57250.228s)
>  hex dump (first 32 bytes):
>    6e 6f 75 76 65 61 75 40 70 63 69 3a 30 30 30 30  nouveau@pci:0000
>    3a 30 35 3a 30 30 2e 30 00 00 00 00 00 00 00 00  :05:00.0........
>  backtrace:
>    [<c145d4eb>] kmemleak_alloc+0x27/0x4d
>    [<c10adb0c>] __kmalloc+0xd4/0x10d
>    [<c125315e>] drm_setversion+0x140/0x1bf
>    [<c12514f2>] drm_ioctl+0x258/0x3d7
>    [<c10bdd42>] vfs_ioctl+0x27/0x9b
>    [<c10bdee2>] do_vfs_ioctl+0x66/0x54b
>    [<c10be3fa>] sys_ioctl+0x33/0x4f
>    [<c102339c>] sysenter_do_call+0x12/0x2c
>    [<ffffffff>] 0xffffffff
>
> for which I wasn't able to find the allocation call-site. Maybe Zeno
> has some out-of-tree DRM module?

I am using the nouveau drivers in the kernel as I got an Nvidia Graphics card.

05:00.0 VGA compatible controller: nVidia Corporation G98 [GeForce
8400 GS] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: ASUSTeK Computer Inc. Device 8321
        Flags: bus master, fast devsel, latency 0, IRQ 16
        Memory at fa000000 (32-bit, non-prefetchable) [size=16M]
        Memory at d0000000 (64-bit, prefetchable) [size=256M]
        Memory at f8000000 (64-bit, non-prefetchable) [size=32M]
        I/O ports at ec00 [size=128]
        [virtual] Expansion ROM at fb000000 [disabled] [size=128K]
        Capabilities: [60] Power Management version 3
        Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
        Capabilities: [78] Express Endpoint, MSI 00
        Capabilities: [100] Virtual Channel <?>
        Capabilities: [128] Power Budgeting <?>
        Capabilities: [600] Vendor Specific Information <?>
        Kernel driver in use: nouveau

Best
Zeno

Download attachment ".config" of type "application/octet-stream" (63537 bytes)

Download attachment "dmesg" of type "application/octet-stream" (15472 bytes)