[PATCH 02/11] xen: Fix and improve handling of device_add usb-host errors

[PATCH 02/11] xen: Fix and improve handling of device_add usb-host errors

[Markus Armbruster]

usbback_portid_add() leaks the error when qdev_device_add() fails.
Fix that.  While there, use the error to improve the error message.

The qemu_opts_from_qdict() similarly leaks on failure.  But any
failure there is a programming error.  Pass &error_abort.

Fixes: 816ac92ef769f9ffc534e49a1bb6177bddce7aa2
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Paul Durrant <paul@xen.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/usb/xen-usb.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/hw/usb/xen-usb.c b/hw/usb/xen-usb.c
index 961190d0f7..42643c3390 100644
--- a/hw/usb/xen-usb.c
+++ b/hw/usb/xen-usb.c
@@ -30,6 +30,7 @@
 #include "hw/usb.h"
 #include "hw/xen/xen-legacy-backend.h"
 #include "monitor/qdev.h"
+#include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qstring.h"
 
@@ -755,13 +756,15 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
     qdict_put_int(qdict, "port", port);
     qdict_put_int(qdict, "hostbus", atoi(busid));
     qdict_put_str(qdict, "hostport", portname);
-    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, &local_err);
-    if (local_err) {
-        goto err;
-    }
+    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict,
+                                &error_abort);
     usbif->ports[port - 1].dev = USB_DEVICE(qdev_device_add(opts, &local_err));
     if (!usbif->ports[port - 1].dev) {
-        goto err;
+        qobject_unref(qdict);
+        xen_pv_printf(&usbif->xendev, 0,
+                      "device %s could not be opened: %s\n",
+                      busid, error_get_pretty(local_err));
+        error_free(local_err);
     }
     qobject_unref(qdict);
     speed = usbif->ports[port - 1].dev->speed;
@@ -793,11 +796,6 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
     usbback_hotplug_enq(usbif, port);
 
     TR_BUS(&usbif->xendev, "port %d attached\n", port);
-    return;
-
-err:
-    qobject_unref(qdict);
-    xen_pv_printf(&usbif->xendev, 0, "device %s could not be opened\n", busid);
 }
 
 static void usbback_process_port(struct usbback_info *usbif, unsigned port)
-- 
2.21.1

RE: [PATCH 02/11] xen: Fix and improve handling of device_add usb-host errors

[Paul Durrant]

> -----Original Message-----
> From: Markus Armbruster <armbru@redhat.com>
> Sent: 24 April 2020 20:20
> To: qemu-devel@nongnu.org
> Cc: Stefano Stabellini <sstabellini@kernel.org>; Anthony Perard <anthony.perard@citrix.com>; Paul
> Durrant <paul@xen.org>; Gerd Hoffmann <kraxel@redhat.com>; xen-devel@lists.xenproject.org
> Subject: [PATCH 02/11] xen: Fix and improve handling of device_add usb-host errors
> 
> usbback_portid_add() leaks the error when qdev_device_add() fails.
> Fix that.  While there, use the error to improve the error message.
> 
> The qemu_opts_from_qdict() similarly leaks on failure.  But any
> failure there is a programming error.  Pass &error_abort.
> 
> Fixes: 816ac92ef769f9ffc534e49a1bb6177bddce7aa2
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: Anthony Perard <anthony.perard@citrix.com>
> Cc: Paul Durrant <paul@xen.org>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: xen-devel@lists.xenproject.org
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  hw/usb/xen-usb.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/usb/xen-usb.c b/hw/usb/xen-usb.c
> index 961190d0f7..42643c3390 100644
> --- a/hw/usb/xen-usb.c
> +++ b/hw/usb/xen-usb.c
> @@ -30,6 +30,7 @@
>  #include "hw/usb.h"
>  #include "hw/xen/xen-legacy-backend.h"
>  #include "monitor/qdev.h"
> +#include "qapi/error.h"
>  #include "qapi/qmp/qdict.h"
>  #include "qapi/qmp/qstring.h"
> 
> @@ -755,13 +756,15 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
>      qdict_put_int(qdict, "port", port);
>      qdict_put_int(qdict, "hostbus", atoi(busid));
>      qdict_put_str(qdict, "hostport", portname);
> -    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, &local_err);
> -    if (local_err) {
> -        goto err;
> -    }
> +    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict,
> +                                &error_abort);
>      usbif->ports[port - 1].dev = USB_DEVICE(qdev_device_add(opts, &local_err));
>      if (!usbif->ports[port - 1].dev) {
> -        goto err;
> +        qobject_unref(qdict);
> +        xen_pv_printf(&usbif->xendev, 0,
> +                      "device %s could not be opened: %s\n",
> +                      busid, error_get_pretty(local_err));
> +        error_free(local_err);

Previously the goto caused the function to bail out. Should there not be a 'return' here?

>      }
>      qobject_unref(qdict);
>      speed = usbif->ports[port - 1].dev->speed;
> @@ -793,11 +796,6 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
>      usbback_hotplug_enq(usbif, port);
> 
>      TR_BUS(&usbif->xendev, "port %d attached\n", port);
> -    return;
> -
> -err:
> -    qobject_unref(qdict);
> -    xen_pv_printf(&usbif->xendev, 0, "device %s could not be opened\n", busid);
>  }
> 
>  static void usbback_process_port(struct usbback_info *usbif, unsigned port)
> --
> 2.21.1

Re: [PATCH 02/11] xen: Fix and improve handling of device_add usb-host errors

[Markus Armbruster]

Paul Durrant <xadimgnik@gmail.com> writes:

>> -----Original Message-----
>> From: Markus Armbruster <armbru@redhat.com>
>> Sent: 24 April 2020 20:20
>> To: qemu-devel@nongnu.org
>> Cc: Stefano Stabellini <sstabellini@kernel.org>; Anthony Perard <anthony.perard@citrix.com>; Paul
>> Durrant <paul@xen.org>; Gerd Hoffmann <kraxel@redhat.com>; xen-devel@lists.xenproject.org
>> Subject: [PATCH 02/11] xen: Fix and improve handling of device_add usb-host errors
>> 
>> usbback_portid_add() leaks the error when qdev_device_add() fails.
>> Fix that.  While there, use the error to improve the error message.
>> 
>> The qemu_opts_from_qdict() similarly leaks on failure.  But any
>> failure there is a programming error.  Pass &error_abort.
>> 
>> Fixes: 816ac92ef769f9ffc534e49a1bb6177bddce7aa2
>> Cc: Stefano Stabellini <sstabellini@kernel.org>
>> Cc: Anthony Perard <anthony.perard@citrix.com>
>> Cc: Paul Durrant <paul@xen.org>
>> Cc: Gerd Hoffmann <kraxel@redhat.com>
>> Cc: xen-devel@lists.xenproject.org
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> ---
>>  hw/usb/xen-usb.c | 18 ++++++++----------
>>  1 file changed, 8 insertions(+), 10 deletions(-)
>> 
>> diff --git a/hw/usb/xen-usb.c b/hw/usb/xen-usb.c
>> index 961190d0f7..42643c3390 100644
>> --- a/hw/usb/xen-usb.c
>> +++ b/hw/usb/xen-usb.c
>> @@ -30,6 +30,7 @@
>>  #include "hw/usb.h"
>>  #include "hw/xen/xen-legacy-backend.h"
>>  #include "monitor/qdev.h"
>> +#include "qapi/error.h"
>>  #include "qapi/qmp/qdict.h"
>>  #include "qapi/qmp/qstring.h"
>> 
>> @@ -755,13 +756,15 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
>>      qdict_put_int(qdict, "port", port);
>>      qdict_put_int(qdict, "hostbus", atoi(busid));
>>      qdict_put_str(qdict, "hostport", portname);
>> -    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, &local_err);
>> -    if (local_err) {
>> -        goto err;
>> -    }
>> +    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict,
>> +                                &error_abort);
>>      usbif->ports[port - 1].dev = USB_DEVICE(qdev_device_add(opts, &local_err));
>>      if (!usbif->ports[port - 1].dev) {
>> -        goto err;
>> +        qobject_unref(qdict);
>> +        xen_pv_printf(&usbif->xendev, 0,
>> +                      "device %s could not be opened: %s\n",
>> +                      busid, error_get_pretty(local_err));
>> +        error_free(local_err);
>
> Previously the goto caused the function to bail out. Should there not be a 'return' here?

Owww, of course.  Thanks!

>
>>      }
>>      qobject_unref(qdict);
>>      speed = usbif->ports[port - 1].dev->speed;
>> @@ -793,11 +796,6 @@ static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
>>      usbback_hotplug_enq(usbif, port);
>> 
>>      TR_BUS(&usbif->xendev, "port %d attached\n", port);
>> -    return;
>> -
>> -err:
>> -    qobject_unref(qdict);
>> -    xen_pv_printf(&usbif->xendev, 0, "device %s could not be opened\n", busid);
>>  }
>> 
>>  static void usbback_process_port(struct usbback_info *usbif, unsigned port)
>> --
>> 2.21.1