On 17/11/2015 11:34, Stefan Hajnoczi wrote: > On Tue, Nov 17, 2015 at 06:20:11PM +0800, Fam Zheng wrote: >> When a request R is absorbed by request M, it is appended to the >> "mr_next" queue led by M, and is completed together with the completion >> of M, in virtio_blk_rw_complete. >> >> During DMA restart in virtio_blk_dma_restart_bh, requests in s->rq are >> parsed and submitted again, possibly with a stale req->mr_next. It could >> be a problem if the request merging in virtio_blk_handle_request hasn't >> refreshed every mr_next pointer, in which case, virtio_blk_rw_complete >> could walk through unexpected requests following the stale pointers. >> >> Fix this by unsetting the pointer in virtio_blk_rw_complete. It is safe >> because this req is either completed and freed right away, or it will be >> restarted and parsed from scratch out of the vq later. >> >> Signed-off-by: Fam Zheng <f...@redhat.com> >> >> --- >> >> v3: Fix as Stefan suggested. >> --- >> hw/block/virtio-blk.c | 4 ++++ >> 1 file changed, 4 insertions(+) > > Thanks, applied to my block tree: > https://github.com/stefanha/qemu/commits/block
I have also tested this one and it works fine. Tested-by: Laurent Vivier <lviv...@redhat.com> Laurent
