* [Qemu-devel] [PATCH] sd: Fix "info qtree" on boards with SD cards
@ 2016-03-15 16:56 Peter Maydell
2016-03-15 20:28 ` [Qemu-devel] [Qemu-arm] " Thomas Hanson
2016-03-16 2:14 ` [Qemu-devel] " hitmoon
0 siblings, 2 replies; 6+ messages in thread
From: Peter Maydell @ 2016-03-15 16:56 UTC (permalink / raw)
To: qemu-arm, qemu-devel
Cc: hitmoon, Paolo Bonzini, Peter Crosthwaite, Andreas Färber, patches
The SD card object is not a SysBusDevice, so don't create it with
qdev_create() if we're not assigning it to a specific bus; use
object_new() instead.
This was causing 'info qtree' to segfault on boards with SD cards,
because qdev_create(NULL, TYPE_FOO) puts the created object on the
system bus, and then we may try to run functions like sysbus_dev_print()
on it, which fail when casting the object to SysBusDevice.
(This is the same mistake that we made with the NAND device
and fixed in commit 6749695eaaf346c1.)
Reported-by: hitmoon <zxq_yx_007@163.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I assume that using qdev_create() for non-SysBus devices is
OK if we are passing in a specific bus pointer, because we do
this already for various things including PCI devices. The
various "properly QOMified" uses of TYPE_SD_CARD do that; only
this sd_init() function for the legacy uses doesn't.
---
hw/sd/sd.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 00c320d..1568057 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -563,17 +563,19 @@ static const VMStateDescription sd_vmstate = {
/* Legacy initialization function for use by non-qdevified callers */
SDState *sd_init(BlockBackend *blk, bool is_spi)
{
+ Object *obj;
DeviceState *dev;
Error *err = NULL;
- dev = qdev_create(NULL, TYPE_SD_CARD);
+ obj = object_new(TYPE_SD_CARD);
+ dev = DEVICE(obj);
qdev_prop_set_drive(dev, "drive", blk, &err);
if (err) {
error_report("sd_init failed: %s", error_get_pretty(err));
return NULL;
}
qdev_prop_set_bit(dev, "spi", is_spi);
- object_property_set_bool(OBJECT(dev), true, "realized", &err);
+ object_property_set_bool(obj, true, "realized", &err);
if (err) {
error_report("sd_init failed: %s", error_get_pretty(err));
return NULL;
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [Qemu-arm] [PATCH] sd: Fix "info qtree" on boards with SD cards
2016-03-15 16:56 [Qemu-devel] [PATCH] sd: Fix "info qtree" on boards with SD cards Peter Maydell
@ 2016-03-15 20:28 ` Thomas Hanson
2016-03-15 20:33 ` Peter Maydell
2016-03-16 2:14 ` [Qemu-devel] " hitmoon
1 sibling, 1 reply; 6+ messages in thread
From: Thomas Hanson @ 2016-03-15 20:28 UTC (permalink / raw)
To: Peter Maydell
Cc: patches, hitmoon, qemu-devel, qemu-arm, Paolo Bonzini,
Andreas Färber
The patch looks good.
Would it also be good to update bus_add_child() so that it NULL-checks
its "bus" parameter before dereferencing it?
-Tom
On 15 March 2016 at 10:56, Peter Maydell <peter.maydell@linaro.org> wrote:
> The SD card object is not a SysBusDevice, so don't create it with
> qdev_create() if we're not assigning it to a specific bus; use
> object_new() instead.
>
> This was causing 'info qtree' to segfault on boards with SD cards,
> because qdev_create(NULL, TYPE_FOO) puts the created object on the
> system bus, and then we may try to run functions like sysbus_dev_print()
> on it, which fail when casting the object to SysBusDevice.
>
> (This is the same mistake that we made with the NAND device
> and fixed in commit 6749695eaaf346c1.)
>
> Reported-by: hitmoon <zxq_yx_007@163.com>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> I assume that using qdev_create() for non-SysBus devices is
> OK if we are passing in a specific bus pointer, because we do
> this already for various things including PCI devices. The
> various "properly QOMified" uses of TYPE_SD_CARD do that; only
> this sd_init() function for the legacy uses doesn't.
> ---
> hw/sd/sd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
> index 00c320d..1568057 100644
> --- a/hw/sd/sd.c
> +++ b/hw/sd/sd.c
> @@ -563,17 +563,19 @@ static const VMStateDescription sd_vmstate = {
> /* Legacy initialization function for use by non-qdevified callers */
> SDState *sd_init(BlockBackend *blk, bool is_spi)
> {
> + Object *obj;
> DeviceState *dev;
> Error *err = NULL;
>
> - dev = qdev_create(NULL, TYPE_SD_CARD);
> + obj = object_new(TYPE_SD_CARD);
> + dev = DEVICE(obj);
> qdev_prop_set_drive(dev, "drive", blk, &err);
> if (err) {
> error_report("sd_init failed: %s", error_get_pretty(err));
> return NULL;
> }
> qdev_prop_set_bit(dev, "spi", is_spi);
> - object_property_set_bool(OBJECT(dev), true, "realized", &err);
> + object_property_set_bool(obj, true, "realized", &err);
> if (err) {
> error_report("sd_init failed: %s", error_get_pretty(err));
> return NULL;
> --
> 1.9.1
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [Qemu-arm] [PATCH] sd: Fix "info qtree" on boards with SD cards
2016-03-15 20:28 ` [Qemu-devel] [Qemu-arm] " Thomas Hanson
@ 2016-03-15 20:33 ` Peter Maydell
2016-03-15 20:41 ` Peter Maydell
0 siblings, 1 reply; 6+ messages in thread
From: Peter Maydell @ 2016-03-15 20:33 UTC (permalink / raw)
To: Thomas Hanson
Cc: Patch Tracking, hitmoon, QEMU Developers, qemu-arm,
Paolo Bonzini, Andreas Färber
On 15 March 2016 at 20:28, Thomas Hanson <thomas.hanson@linaro.org> wrote:
> The patch looks good.
>
> Would it also be good to update bus_add_child() so that it NULL-checks
> its "bus" parameter before dereferencing it?
No, I think it's just a programming error to call qdev_set_parent_bus()
with a NULL bus parameter, so crashing is fine.
(The problem fixed by this patch doesn't involve calling bus_add_child()
with a NULL pointer, in any case -- qdev_try_create() will handle
a NULL bus pointer as "use the default system bus", so by the time
it gets to bus_add_child() the bus pointer is never NULL. It's
using the default bus at all that causes things to go wrong much
later on down the line.)
thanks
-- PMM
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [Qemu-arm] [PATCH] sd: Fix "info qtree" on boards with SD cards
2016-03-15 20:33 ` Peter Maydell
@ 2016-03-15 20:41 ` Peter Maydell
2016-03-16 13:22 ` Thomas Hanson
0 siblings, 1 reply; 6+ messages in thread
From: Peter Maydell @ 2016-03-15 20:41 UTC (permalink / raw)
To: Thomas Hanson
Cc: Patch Tracking, hitmoon, QEMU Developers, qemu-arm,
Paolo Bonzini, Andreas Färber
On 15 March 2016 at 20:33, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 15 March 2016 at 20:28, Thomas Hanson <thomas.hanson@linaro.org> wrote:
>> The patch looks good.
>>
>> Would it also be good to update bus_add_child() so that it NULL-checks
>> its "bus" parameter before dereferencing it?
>
> No, I think it's just a programming error to call qdev_set_parent_bus()
> with a NULL bus parameter, so crashing is fine.
...but it might be helpful to assert in qdev_try_create() that
if we're using the default bus then the object is a sysbus
device object. At least then the problem will be immediately
clear rather than only showing up if you run a monitor command
later.
thanks
-- PMM
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH] sd: Fix "info qtree" on boards with SD cards
2016-03-15 16:56 [Qemu-devel] [PATCH] sd: Fix "info qtree" on boards with SD cards Peter Maydell
2016-03-15 20:28 ` [Qemu-devel] [Qemu-arm] " Thomas Hanson
@ 2016-03-16 2:14 ` hitmoon
1 sibling, 0 replies; 6+ messages in thread
From: hitmoon @ 2016-03-16 2:14 UTC (permalink / raw)
To: Peter Maydell, qemu-arm, qemu-devel
Cc: Paolo Bonzini, Peter Crosthwaite, Andreas Färber, patches
在 2016年03月16日 00:56, Peter Maydell 写道:
> The SD card object is not a SysBusDevice, so don't create it with
> qdev_create() if we're not assigning it to a specific bus; use
> object_new() instead.
>
> This was causing 'info qtree' to segfault on boards with SD cards,
> because qdev_create(NULL, TYPE_FOO) puts the created object on the
> system bus, and then we may try to run functions like sysbus_dev_print()
> on it, which fail when casting the object to SysBusDevice.
>
> (This is the same mistake that we made with the NAND device
> and fixed in commit 6749695eaaf346c1.)
>
> Reported-by: hitmoon <zxq_yx_007@163.com>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> I assume that using qdev_create() for non-SysBus devices is
> OK if we are passing in a specific bus pointer, because we do
> this already for various things including PCI devices. The
> various "properly QOMified" uses of TYPE_SD_CARD do that; only
> this sd_init() function for the legacy uses doesn't.
> ---
> hw/sd/sd.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
> index 00c320d..1568057 100644
> --- a/hw/sd/sd.c
> +++ b/hw/sd/sd.c
> @@ -563,17 +563,19 @@ static const VMStateDescription sd_vmstate = {
> /* Legacy initialization function for use by non-qdevified callers */
> SDState *sd_init(BlockBackend *blk, bool is_spi)
> {
> + Object *obj;
> DeviceState *dev;
> Error *err = NULL;
>
> - dev = qdev_create(NULL, TYPE_SD_CARD);
> + obj = object_new(TYPE_SD_CARD);
> + dev = DEVICE(obj);
> qdev_prop_set_drive(dev, "drive", blk, &err);
> if (err) {
> error_report("sd_init failed: %s", error_get_pretty(err));
> return NULL;
> }
> qdev_prop_set_bit(dev, "spi", is_spi);
> - object_property_set_bool(OBJECT(dev), true, "realized", &err);
> + object_property_set_bool(obj, true, "realized", &err);
> if (err) {
> error_report("sd_init failed: %s", error_get_pretty(err));
> return NULL;
Nice patch !
Reviewed-by: xiaoqiang.zhao <zxq_yx_007@163.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [Qemu-arm] [PATCH] sd: Fix "info qtree" on boards with SD cards
2016-03-15 20:41 ` Peter Maydell
@ 2016-03-16 13:22 ` Thomas Hanson
0 siblings, 0 replies; 6+ messages in thread
From: Thomas Hanson @ 2016-03-16 13:22 UTC (permalink / raw)
To: Peter Maydell
Cc: Patch Tracking, hitmoon, QEMU Developers, qemu-arm,
Paolo Bonzini, Andreas Färber
Sounds like a good idea. Much easier to fix a problem with an
explicit error than to chase a seg fault.
On 15 March 2016 at 14:41, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 15 March 2016 at 20:33, Peter Maydell <peter.maydell@linaro.org> wrote:
>> On 15 March 2016 at 20:28, Thomas Hanson <thomas.hanson@linaro.org> wrote:
>>> The patch looks good.
>>>
>>> Would it also be good to update bus_add_child() so that it NULL-checks
>>> its "bus" parameter before dereferencing it?
>>
>> No, I think it's just a programming error to call qdev_set_parent_bus()
>> with a NULL bus parameter, so crashing is fine.
>
> ...but it might be helpful to assert in qdev_try_create() that
> if we're using the default bus then the object is a sysbus
> device object. At least then the problem will be immediately
> clear rather than only showing up if you run a monitor command
> later.
>
> thanks
> -- PMM
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-03-16 13:22 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2016-03-15 16:56 [Qemu-devel] [PATCH] sd: Fix "info qtree" on boards with SD cards Peter Maydell
2016-03-15 20:28 ` [Qemu-devel] [Qemu-arm] " Thomas Hanson
2016-03-15 20:33 ` Peter Maydell
2016-03-15 20:41 ` Peter Maydell
2016-03-16 13:22 ` Thomas Hanson
2016-03-16 2:14 ` [Qemu-devel] " hitmoon
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