Re: [PATCH] xhci: Fix memory leak in xhci_kick_epctx when poweroff GuestOS

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 1/10/20 11:58 AM, kuhn.chenqun@huawei.com wrote:
> From: Chen Qun <kuhn.chenqun@huawei.com>
> 
> start vm with libvirt, when GuestOS running, enter poweroff command using
> the xhci keyboard, then ASAN shows memory leak stack：
> 
> Direct leak of 80 byte(s) in 5 object(s) allocated from:
>      #0 0xfffd1e6431cb in __interceptor_malloc (/lib64/libasan.so.4+0xd31cb)
>      #1 0xfffd1e107163 in g_malloc (/lib64/libglib-2.0.so.0+0x57163)
>      #2 0xaaad39051367 in qemu_sglist_init /qemu/dma-helpers.c:43
>      #3 0xaaad3947c407 in pci_dma_sglist_init /qemu/include/hw/pci/pci.h:842
>      #4 0xaaad3947c407 in xhci_xfer_create_sgl /qemu/hw/usb/hcd-xhci.c:1446
>      #5 0xaaad3947c407 in xhci_setup_packet /qemu/hw/usb/hcd-xhci.c:1618
>      #6 0xaaad3948625f in xhci_submit /qemu/hw/usb/hcd-xhci.c:1827
>      #7 0xaaad3948625f in xhci_fire_transfer /qemu/hw/usb/hcd-xhci.c:1839
>      #8 0xaaad3948625f in xhci_kick_epctx /qemu/hw/usb/hcd-xhci.c:1991
>      #9 0xaaad3948f537 in xhci_doorbell_write /qemu/hw/usb/hcd-xhci.c:3158
>      #10 0xaaad38bcbfc7 in memory_region_write_accessor /qemu/memory.c:483
>      #11 0xaaad38bc654f in access_with_adjusted_size /qemu/memory.c:544
>      #12 0xaaad38bd1877 in memory_region_dispatch_write /qemu/memory.c:1482
>      #13 0xaaad38b1c77f in flatview_write_continue /qemu/exec.c:3167
>      #14 0xaaad38b1ca83 in flatview_write /qemu/exec.c:3207
>      #15 0xaaad38b268db in address_space_write /qemu/exec.c:3297
>      #16 0xaaad38bf909b in kvm_cpu_exec /qemu/accel/kvm/kvm-all.c:2383
>      #17 0xaaad38bb063f in qemu_kvm_cpu_thread_fn /qemu/cpus.c:1246
>      #18 0xaaad39821c93 in qemu_thread_start /qemu/util/qemu-thread-posix.c:519
>      #19 0xfffd1c8378bb  (/lib64/libpthread.so.0+0x78bb)
>      #20 0xfffd1c77616b  (/lib64/libc.so.6+0xd616b)
> 
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
> ---
>   hw/usb/hcd-xhci.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> index 80988bb305..0d3d96d05a 100644
> --- a/hw/usb/hcd-xhci.c
> +++ b/hw/usb/hcd-xhci.c
> @@ -2000,6 +2000,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
>           if (xfer != NULL && xfer->running_retry) {
>               DPRINTF("xhci: xfer nacked, stopping schedule\n");
>               epctx->retry = xfer;
> +            xhci_xfer_unmap(xfer);

Shouldn't we use xhci_ep_free_xfer() instead?
Also, it would be cleaner if you set it to NULL.

>               break;
>           }
>           if (count++ > TRANSFER_LIMIT) {
>