Am 04.03.2015 um 15:24 hat Max Reitz geschrieben: > On 2015-03-04 at 09:20, Kevin Wolf wrote: > >Am 04.03.2015 um 15:07 hat Max Reitz geschrieben: > >>On 2015-03-04 at 09:02, Kevin Wolf wrote: > >>>Am 09.02.2015 um 18:11 hat Max Reitz geschrieben: > >>>>Only call bdrv_key_required() on the BlockDriverState if the > >>>>BlockBackend has an inserted medium. > >>>> > >>>>Signed-off-by: Max Reitz <[email protected]> > >>>>Reviewed-by: Eric Blake <[email protected]> > >>>>--- > >>>> hw/usb/dev-storage.c | 2 +- > >>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>> > >>>>diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c > >>>>index 4539733..3123baf 100644 > >>>>--- a/hw/usb/dev-storage.c > >>>>+++ b/hw/usb/dev-storage.c > >>>>@@ -638,7 +638,7 @@ static void usb_msd_realize_storage(USBDevice *dev, > >>>>Error **errp) > >>>> usb_msd_handle_reset(dev); > >>>> s->scsi_dev = scsi_dev; > >>>>- if (bdrv_key_required(blk_bs(blk))) { > >>>>+ if (blk_is_inserted(blk) && bdrv_key_required(blk_bs(blk))) { > >>>> if (cur_mon) { > >>>> monitor_read_bdrv_key_start(cur_mon, blk_bs(blk), > >>>> usb_msd_password_cb, s); > >>>Why would bdrv_key_required() ever return true when no medium is > >>>inserted? Sounds like a bug to me, like not resetting state correctly on > >>>bdrv_close() of an encrypted image. > >>The point is that blk_bs(blk) might be NULL. > >This is not what blk_is_inserted() is checking. It happens to protect > >you against segfaults because it's robust against using NULL, but with > >an existing BDS, checking whether there is a medium inserted (in the > >physical device for passthrough drivers) doesn't make sense. > > Not right now it's not. See patch 6.
Patch 6 looks unrelated, at least in v2. But if you're trying to say that I looked at the wrong version, you're right: It doesn't protect you against segfaults at this point yet (which is okay, because blk->bs can't be NULL yet), it only performs the misguided inserted check. Doesn't answer my initial question or make that check any better. Kevin
