[vbox-dev] Memory leak in VBox 4.1.0 r73009

[Larry Finger]

On 08/22/2011 10:25 AM, Frank Mehnert wrote:
> Larry,
>
> On Sunday 14 August 2011 03:39:52 Larry Finger wrote:
>> Kmemleak shows the following leak in the VB kernel module for version 4.1.0
>> r73009 (x86_64):
>>
>> unreferenced object 0xffff88006baf1d00 (size 128):
>>     comm "VirtualBox", pid 549, jiffies 4314134921 (age 30845.876s)
>>     hex dump (first 32 bytes):
>>       19 01 09 18 00 00 00 80 58 00 00 00 58 00 00 00  ........X...X...
>>       03 01 92 18 0f 32 9c 65 2e 2e 00 00 ad 4e ad de  .....2.e.....N..
>>     backtrace:
>>       [<ffffffff81122d77>] create_object+0x127/0x2b0
>>       [<ffffffff813580b1>] kmemleak_alloc+0x21/0x50
>>       [<ffffffff8111cd33>] __kmalloc+0x113/0x1c0
>>       [<ffffffffa04c21ca>] rtR0MemAllocEx+0x5a/0x160 [vboxdrv]
>>       [<ffffffffa04bff03>] VBoxHost_RTMemAllocTag+0x13/0x30 [vboxdrv]
>>       [<ffffffffa04c4cfb>] VBoxHost_RTSemFastMutexCreate+0x1b/0x90 [vboxdrv]
>>       [<ffffffffa04d7ff4>] g_abExecMemory+0x28f4/0x180000 [vboxdrv]
>>       [<ffffffffa04eaef9>] g_abExecMemory+0x157f9/0x180000 [vboxdrv]
>>       [<ffffffffa04bd619>] supdrvIOCtl+0x11b9/0x2820 [vboxdrv]
>>       [<ffffffffa04b8435>] VBoxDrvLinuxIOCtl+0x135/0x200 [vboxdrv]
>>       [<ffffffff81137de6>] do_vfs_ioctl+0x96/0x550
>>       [<ffffffff811382ea>] sys_ioctl+0x4a/0x80
>>       [<ffffffff8136befb>] system_call_fastpath+0x16/0x1b
>>       [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> I have not yet tried to find the source of the leak.
>
> is this really a leak? I see similar kmemleak complaints if a VM is started
> but these complaints vanish as soon as the VM is terminated. Also, I also
> don't see that the number of the complaints is growing.

It very well may be a false positive. I'm running kmemleak to debug various 
wireless drivers and noted a couple of those in the logs. If it disappears after 
VB is closed, then kmemleak just couldn't find the reference to it. I'll keep an 
eye on it and report again if the leak is still there after closing VB.

Larry