Am 09.02.2020 um 18:51 hat Hikaru Nishida geschrieben:
> Before this commit, BDRVVVFATState.qcow is unrefed in write_target_close
> on closing backing bdrv of vvfat. However, qcow bdrv is opend as a child
> of vvfat in enable_write_target() so it will be also unrefed on closing
> vvfat itself. This causes use-after-free of qcow on freeing vvfat which
> has backing bdrv and qcow bdrv as children in this order because
> bdrv_close(vvfat) tries to free qcow bdrv after freeing backing bdrv
> as QLIST_FOREACH_SAFE() loop keeps next pointer, but BdrvChild of qcow
> is already freed in bdrv_close(backing bdrv).
> Signed-off-by: Hikaru Nishida <>

Thanks, applied to the block branch.


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