| Message ID | 1466667001-10167-1-git-send-email-kwolf@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 06/23/2016 01:30 AM, Kevin Wolf wrote: > BlockBackend has only a single pointer to its guest device, so it makes > sure that only a single guest device is attached to it. device-add > returns an error if you try to attach a second device to a BB. In order > to make the error message nicer, -device that manually connects to a > if=none block device get a different message than -drive that implicitly > creates a guest device. The if=... option is stored in DriveInfo. > > However, since blockdev-add exists, not every BlockBackend has a > DriveInfo any more. Check that it exists before we dereference it. > > QMP reproducer resulting in a segfault: > > {"execute":"blockdev-add","arguments":{"options":{"id":"disk","driver":"file","filename":"/tmp/test.img"}}} > {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} > {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > hw/core/qdev-properties-system.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Reviewed-by: Eric Blake <eblake@redhat.com>
On Thu, Jun 23, 2016 at 09:30:01AM +0200, Kevin Wolf wrote: > BlockBackend has only a single pointer to its guest device, so it makes > sure that only a single guest device is attached to it. device-add > returns an error if you try to attach a second device to a BB. In order > to make the error message nicer, -device that manually connects to a > if=none block device get a different message than -drive that implicitly > creates a guest device. The if=... option is stored in DriveInfo. > > However, since blockdev-add exists, not every BlockBackend has a > DriveInfo any more. Check that it exists before we dereference it. > > QMP reproducer resulting in a segfault: > > {"execute":"blockdev-add","arguments":{"options":{"id":"disk","driver":"file","filename":"/tmp/test.img"}}} > {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} > {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > hw/core/qdev-properties-system.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Am 23.06.2016 um 09:30 hat Kevin Wolf geschrieben: > BlockBackend has only a single pointer to its guest device, so it makes > sure that only a single guest device is attached to it. device-add > returns an error if you try to attach a second device to a BB. In order > to make the error message nicer, -device that manually connects to a > if=none block device get a different message than -drive that implicitly > creates a guest device. The if=... option is stored in DriveInfo. > > However, since blockdev-add exists, not every BlockBackend has a > DriveInfo any more. Check that it exists before we dereference it. > > QMP reproducer resulting in a segfault: > > {"execute":"blockdev-add","arguments":{"options":{"id":"disk","driver":"file","filename":"/tmp/test.img"}}} > {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} > {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> Applied to my block branch. Kevin
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c index 623be94..c5cc9cf 100644 --- a/hw/core/qdev-properties-system.c +++ b/hw/core/qdev-properties-system.c @@ -91,7 +91,7 @@ static void parse_drive(DeviceState *dev, const char *str, void **ptr, if (blk_attach_dev(blk, dev) < 0) { DriveInfo *dinfo = blk_legacy_dinfo(blk); - if (dinfo->type != IF_NONE) { + if (dinfo && dinfo->type != IF_NONE) { error_setg(errp, "Drive '%s' is already in use because " "it has been automatically connected to another " "device (did you need 'if=none' in the drive options?)",
BlockBackend has only a single pointer to its guest device, so it makes sure that only a single guest device is attached to it. device-add returns an error if you try to attach a second device to a BB. In order to make the error message nicer, -device that manually connects to a if=none block device get a different message than -drive that implicitly creates a guest device. The if=... option is stored in DriveInfo. However, since blockdev-add exists, not every BlockBackend has a DriveInfo any more. Check that it exists before we dereference it. QMP reproducer resulting in a segfault: {"execute":"blockdev-add","arguments":{"options":{"id":"disk","driver":"file","filename":"/tmp/test.img"}}} {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} {"execute":"device_add","arguments":{"driver":"virtio-blk-pci","drive":"disk"}} Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- hw/core/qdev-properties-system.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)