Re: [Qemu-devel] [Xen-devel] memory leak in block/xen_disk in qemu-3.x

[Paul Durrant]

> -----Original Message-----
> From: Xen-devel [mailto:address@hidden On Behalf
> Of Olaf Hering
> Sent: 11 December 2018 15:31
> To: address@hidden; address@hidden
> Subject: [Xen-devel] memory leak in block/xen_disk in qemu-3.x
> 
> What are the live time rules of ioreq->buf?
> 
> In my testing the memory usage of qemu is constantly growing from about
> 250MB to several GB after a few days.

Are you perhaps running into the problem addressed by this patch?

https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg00244.html

  Paul

> 
> Some debugging shows that ioreq_runio_qemu_aio() overwrites ioreq->buf,
> which contributes to the leak. In addition, ioreq_reset() also just
> globbers iorew->buf. While this was observed with a backport of xen_disk
> changes to qemu-2.9, the code in xen_disk.c did not change in this
> regard. I changed the code to call qemu_vfree(ioreq->buf) in the few
> places that globber the pointer, that fixes the leak for me.
> 
> Right now neither qemu-3.0 nor 3.1 for me, so I can not test
> qemu.git#master if it eventually behaves different than
> qemu.git#stable-2.9+backport.
> 
> Olaf