linux-kernel - 答复: problem with kmemleak

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Date:	Thu, 12 May 2011 17:59:25 +0800
From:	chenxi <chenxi05@...du.com>
To:	'Maxin B John' <maxin.john@...il.com>
CC:	<linux-kernel@...r.kernel.org>
Subject: 答复: problem with kmemleak

Thx, Maxin :)
ok
I did steps below:
1 make oldconfig 
2 vim .config
  ...
  CONFIG_DEBUG_FS = y
  CONFIG_DEBUG_KMEMLEAK = y
  CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE = 1200
  ...
3 make ; make modules ; and replace the kernel; reboot
4 mount -t debugfs debugfs /sys/kernel/debug
4 I wrote a module like this
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/vmalloc.h>

void myfunc(void)
{
        char *ptr;
        ptr = vmalloc(512);
        ptr = vmalloc(512);
        ptr = vmalloc(512);
}

int hello_init(void)
{
        printk(KERN_ALERT "Hello World");
        myfunc();
        return 0;
}

static void hello_exit(void)
{
        printk(KERN_ALERT "Goodbye World");
}

module_init(hello_init);
module_exit(hello_exit);

MODULE_LICENSE("GPL v2");

5 clear the kmemleak
 Echo clear > /sys/kernel/debug/kmemleak
6 insmod the module
 Insmod xxx.ko
7 echo scan > /sys/kenel/debug/kmemleak
8 watch it
 Cat / sys/kenel/debug/kmemleak
 >> unreferenced object 0xffffc90012d27000 (size 64):
>>
>>  comm "insmod", pid 13092, jiffies 4298369684
>>
>>  hex dump (first 32 bytes):
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>  backtrace:
>>
>>    [<ffffffffffffffff>] 0xffffffffffffffff
>>
And I can only get the backtrace [<ffffffffffffffff>]

BTW the kernel's version is 2.6.32.

Thx to Maxin again~~~:)
-----邮件原件-----
发件人: linux-kernel-owner@...r.kernel.org [mailto:linux-kernel-owner@...r.kernel.org] 代表 Maxin B John
发送时间: 2011年5月12日 17:44
收件人: ttlxzz ccc
抄送: linux-kernel@...r.kernel.org
主题: Re: problem with kmemleak

Hi,

Could you please share some more information about your setup ?

Regards,
Maxin

On Thu, May 12, 2011 at 4:13 AM, ttlxzz ccc <boyzccc@...il.com> wrote:
> help~~~：） please ！thx！！
>
> On Thu, May 12, 2011 at 10:06 AM, ttlxzz ccc <boyzccc@...il.com> wrote:
>> Hi, all:
>>
>>
>>
>> I just want to use kmemleak, so I make the CONFIG_DEBUG_KMEMLEAK and
>> CONFIG_DEBUG_FS on, mount the debugfs.
>>
>> But when I insmod mm/kmemleak-test.ko, echo scan >
>> /sys/kernel/debug/kmemleak and cat /sys/kernel/debug/kmemleak. I just
>> see this:
>>
>> unreferenced object 0xffffc90012d21000 (size 64):
>>
>>  comm "insmod", pid 13092, jiffies 4298369684
>>
>>  hex dump (first 32 bytes):
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>  backtrace:
>>
>>    [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> unreferenced object 0xffffc90012d24000 (size 64):
>>
>>  comm "insmod", pid 13092, jiffies 4298369684
>>
>>  hex dump (first 32 bytes):
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>  backtrace:
>>
>>    [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> unreferenced object 0xffffc90012d27000 (size 64):
>>
>>  comm "insmod", pid 13092, jiffies 4298369684
>>
>>  hex dump (first 32 bytes):
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>
>>  backtrace:
>>
>>    [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> There is no other backtrace except [<ffffffffffffffff>]
>> 0xffffffffffffffff. Then I read the mm/kmemleak.c. In
>> kmemleak_seq_show(), I find that the object->trace_len is 1.
>>
>>
>>
>> How can I get the full backtrace?
>>
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