http://openwall.com/lists/oss-security/2017/08/21/2 https://lists.gnu.org/archive/html/qemu-devel/2017-08/msg01850.html The block backend changed in a way that flushing empty CDROM drives now crashes. Amend IDE to avoid doing so until the root problem can be addressed for 2.11. Original patch by John Snow . Reported-by: Kieron Shorrock Signed-off-by: Stefan Hajnoczi --- hw/ide/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/hw/ide/core.c b/hw/ide/core.c index 0b48b64d3a..bea39536b0 100644 --- a/hw/ide/core.c +++ b/hw/ide/core.c @@ -1063,7 +1063,15 @@ static void ide_flush_cache(IDEState *s) s->status |= BUSY_STAT; ide_set_retry(s); block_acct_start(blk_get_stats(s->blk), &s->acct, 0, BLOCK_ACCT_FLUSH); - s->pio_aiocb = blk_aio_flush(s->blk, ide_flush_cb, s); + + if (blk_bs(s->blk)) { + s->pio_aiocb = blk_aio_flush(s->blk, ide_flush_cb, s); + } else { + /* XXX blk_aio_flush() crashes when blk_bs(blk) is NULL, remove this + * temporary workaround when blk_aio_*() functions handle NULL blk_bs. + */ + ide_flush_cb(s, 0); + } } static void ide_cfata_metadata_inquiry(IDEState *s) -- 2.13.3