[Pkg-xen-devel] Bug#767295: Bug#767295: Bug#767295: xl: apparent memory leak

[Ian Campbell]

On Sun, 2014-11-09 at 07:28 -0500, Gedalya wrote:
> On 11/09/2014 07:18 AM, Gedalya wrote:
> > That memory block is just a bit larger than the size of the initrd in 
> > the VM, could there be a connection? 
> 
> Nope. I changed the initrd to 2.6mb and that memory block is still 
> exactly at 23852 / 14464  / 14464.
> Actually the process size is around 12 mb when pygrub is counting down 
> to boot, then jumps up to 14+ mb

Running under gdb and dumping the contents of the leak block it appears
to be the uncompressed payout of the vmlinuz

i.e. using bzexplode[0]:

        $ file../bzexplode /boot/vmlinuz-3.16-3-amd64 | xzcat | od -t x4 | less
        0000000 464c457f 00010102 00000000 00000000
        0000020 003e0002 00000001 01000000 00000000
        0000040 00000040 00000000 00e1f160 00000000
        
vs:
        (gdb) x/32xw 0x00007fffea8b5000
        0x7fffea8b5000:	0x00000000	0x00000000	0x0174b002	0x00000000
        0x7fffea8b5010:	0x464c457f	0x00010102	0x00000000	0x00000000
        0x7fffea8b5020:	0x003e0002	0x00000001	0x01000000	0x00000000

(the first 4 words are no doubt the allocator's metadata).

I think I can see the leak now, it seems to be present in the latest
upstream git tree too.

Ian.

[0]
http://lists.xen.org/archives/html/xen-devel/2012-02/txtVnQboj3Whe.txt