Date:	Mon, 31 Aug 2009 10:50:54 -0700
From:	"Luis R. Rodriguez" <mcgrof@...il.com>
To:	Catalin Marinas <catalin.marinas@....com>,
	"John W. Linville" <linville@...driver.com>,
	"H. Peter Anvin" <hpa@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	linux-wireless <linux-wireless@...r.kernel.org>
Subject: Re: memleaks, acpi + ext4 + tty

On Mon, Aug 31, 2009 at 1:23 AM, Luis R. Rodriguez<mcgrof@...il.com> wrote:
> On Fri, Aug 28, 2009 at 3:09 PM, Luis R. Rodriguez<mcgrof@...il.com> wrote:
>> On Fri, Aug 28, 2009 at 2:50 PM, Luis R. Rodriguez<mcgrof@...il.com> wrote:
>>> On Fri, Aug 28, 2009 at 9:52 AM, Luis R. Rodriguez<mcgrof@...il.com> wrote:
>>>> On Fri, Aug 28, 2009 at 9:32 AM, Catalin Marinas<catalin.marinas@....com> wrote:
>>>>> "Luis R. Rodriguez" <mcgrof@...il.com> wrote:
>>>>>> I have an assorted collection of kmemleak reports for acpi, ext4 and
>>>>>> tty, not sure how to read these yet to fix so figure I'd at least post
>>>>>> them. To reproduce I can just dd=/dev/zero to some big file and played
>>>>>> some video.
>>>>>
>>>>> If you do a few echo scan > /sys/kernel/debug/kmemleak, do they
>>>>> disappear (i.e. transient false positives)?
>>>>
>>>> Sure, I will once on rc8.
>>>>
>>>>> Which kernel version is this?
>>>>
>>>> v2.6.31-rc7-33172-gf4a9f9a
>>>>
>>>> This is from wireless-testing, which has wireless patches on top of
>>>> rc7. John just rebased to rc8 so will give that a shot at work.
>>>>
>>>>>> unreferenced object 0xffff88003e0015c0 (size 64):
>>>>>>   comm "swapper", pid 1, jiffies 4294892352
>>>>>>   backtrace:
>>>>>>     [<ffffffff81121fad>] create_object+0x13d/0x2d0
>>>>>>     [<ffffffff81122265>] kmemleak_alloc+0x25/0x60
>>>>>>     [<ffffffff81118a03>] kmem_cache_alloc_node+0x193/0x200
>>>>>>     [<ffffffff8152509e>] process_zones+0x70/0x1cd
>>>>>>     [<ffffffff81525230>] pageset_cpuup_callback+0x35/0x92
>>>>>>     [<ffffffff8152c9b7>] notifier_call_chain+0x47/0x90
>>>>>>     [<ffffffff81078549>] __raw_notifier_call_chain+0x9/0x10
>>>>>>     [<ffffffff81523f25>] _cpu_up+0x75/0x130
>>>>>>     [<ffffffff8152403a>] cpu_up+0x5a/0x6a
>>>>>>     [<ffffffff8181969e>] kernel_init+0xcc/0x1ba
>>>>>>     [<ffffffff810130ca>] child_rip+0xa/0x20
>>>>>>     [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>
>>>>> Can't really tell. Maybe a false positive caused by kmemleak not
>>>>> scanning the pgdata node_zones. Can you post your .config file?
>>>>
>>>> Sure, attached.
>>>>
>>>>>> unreferenced object 0xffff88003cb5f700 (size 64):
>>>>>>   comm "swapper", pid 1, jiffies 4294892459
>>>>>>   backtrace:
>>>>>>     [<ffffffff81121fad>] create_object+0x13d/0x2d0
>>>>>>     [<ffffffff81122265>] kmemleak_alloc+0x25/0x60
>>>>>>     [<ffffffff81119f3b>] __kmalloc+0x16b/0x250
>>>>>>     [<ffffffff812bb549>] kzalloc+0xf/0x11
>>>>>>     [<ffffffff812bbb53>] acpi_add_single_object+0x58e/0xd3c
>>>>>>     [<ffffffff812bc51c>] acpi_bus_scan+0x125/0x1af
>>>>>>     [<ffffffff81842361>] acpi_scan_init+0xc8/0xe9
>>>>>>     [<ffffffff8184211c>] acpi_init+0x21f/0x265
>>>>>>     [<ffffffff8100a05b>] do_one_initcall+0x4b/0x1b0
>>>>>>     [<ffffffff81819736>] kernel_init+0x164/0x1ba
>>>>>>     [<ffffffff810130ca>] child_rip+0xa/0x20
>>>>>>     [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>
>>>>> I get ACPI reports as well and they may be real leaks. However, I
>>>>> didn't have time to analyse the code (pretty complicated reference
>>>>> counting).
>>>>
>>>> Heh OK thanks for reviewing them though.
>>>>
>>>>>> unreferenced object 0xffff880039571800 (size 1024):
>>>>>>   comm "exe", pid 1168, jiffies 4294893410
>>>>>>   backtrace:
>>>>>>     [<ffffffff81121fad>] create_object+0x13d/0x2d0
>>>>>>     [<ffffffff81122265>] kmemleak_alloc+0x25/0x60
>>>>>>     [<ffffffff81119f3b>] __kmalloc+0x16b/0x250
>>>>>>     [<ffffffff811e1d71>] ext4_mb_init+0x1a1/0x590
>>>>>>     [<ffffffff811d2da3>] ext4_fill_super+0x1df3/0x26c0
>>>>>>     [<ffffffff8112774f>] get_sb_bdev+0x16f/0x1b0
>>>>>>     [<ffffffff811c8fd3>] ext4_get_sb+0x13/0x20
>>>>>>     [<ffffffff81127216>] vfs_kern_mount+0x76/0x180
>>>>>>     [<ffffffff8112738d>] do_kern_mount+0x4d/0x130
>>>>>>     [<ffffffff8113fc57>] do_mount+0x307/0x8b0
>>>>>>     [<ffffffff8114028f>] sys_mount+0x8f/0xe0
>>>>>>     [<ffffffff81011f02>] system_call_fastpath+0x16/0x1b
>>>>>>     [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>
>>>>> The ext4 reports are real leaks and patch was posted here -
>>>>> http://lkml.org/lkml/2009/7/15/62. However, it hasn't been merged into
>>>>> mainline yet (I cc'ed Aneesh).
>>>>>
>>>>> The patch is merged in my "kmemleak-fixes" branch on
>>>>> git://linux-arm.org/linux-2.6.git.
>>>>
>>>> Will try to suck them out and try them.
>>>
>>> OK -- tested rc8 + a pull of your tree into mine. The bootup was
>>> really slow and something was just not going right. After a while
>>> memleak complained it had 8 kmemleak logs but I was not able to get my
>>> system usable enough to cat the file.
>>>
>>> In cases like these I wish I would hookup my ctrl-alt-del to kexec() a
>>> safe kernel.
>>>
>>> After a long period of time it seems X wished it would start, it tried
>>> and then flashed back to the tty. This kept repeating in a loop.
>>>
>>> I am not sure if the culprit was rc8 or the kmemleak branch merge --
>>> I'll find out after I boot into rc8 in a few.
>>
>> rc8 busted my bootup, the issues are present with just
>> wireless-testing. I highly doubt the issues are wireless-testing
>> related so I will not bisect there. Since I am unable to get anything
>> useful from the kernel to determine what may have gone sour, any
>> suggestions on a path to bisect, or should I just do the whole tree?
>
> I tried 2.6.31-rc8 from hpa's linux-2.6-allstable.git tree instead of
> Linus [1] as I already had that tree, git describe says:
>
> v2.6.31-rc8-15-gadda766
>
> Testing this would be the same as testing Linus' blessed rc8 --
> correct me I'm wrong. Contrary to what I expected this tree with the
> same config works well!
>
> I have compiled a fresh checkout of wireless-testing origin/master to
> double check the issue and it is indeed only present on
> wireless-testing. A diff stat between John's merge of 2.6.31-rc8 and
> current master branch on wireless-testing [2] doesn't reveal much
> other than wireless specific stuff, as expected, so it seems this may
> after all be introduced in a recent patches in wireless-testing. I
> still find this a bit odd given I see no others reporting major
> issues. My boot doesn't go very far, it stalls for a while after input
> devices are being detected, then it spits out a kmemleak warning about
> 13 kmemleaks. Here's a picture [3]. I didn't bother waiting as I did
> last time for X to try to come up, something is really wrong. I'll
> bisect wireless-testing in the morning, starting with a good marker at
> merge-2009-08-28 as that is when John pulled 2.6.31-rc8 (and I confirm
> a diff stat between that and v2.6.31-rc8 yields nothing as it should)
> and current master as the bad marker. I have 9 steps to go, will leave
> first step compiling overnight.
>
> [1] git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-allstable.git
> [2] git diff --stat merge-2009-08-28..HEAD
> [3] http://bombadil.infradead.org/~mcgrof/images/2009/08/lag-wl-2009-08-31.jpg
> [4] git diff --stat merge-2009-08-28..v2.6.31-rc8

Hah, well this makes no sense:

mcgrof@tux ~/wireless-testing (git::(no branch))$ git bisect bad
a4e774ca75e5f2d8347b4d9746a2e0a9a4fc521b is first bad commit
commit a4e774ca75e5f2d8347b4d9746a2e0a9a4fc521b
Author: John W. Linville <linville@...driver.com>
Date:   Wed Feb 27 16:04:18 2008 -0500

    Add localversion-wireless to identify builds from this tree.

    Signed-off-by: John W. Linville <linville@...driver.com>

:000000 100644 0000000000000000000000000000000000000000
6a05d60db3b21d9c0a0b93b831c6ea453dc98785 A	localversion-wireless

I'll try a fresh branch on merge-2009-08-28 ..

  Luis
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