On Mon, Aug 17, 2020 at 05:52:40PM +0800, Ming Lei wrote:
> 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support") starts
> to support multi-range discard for virtio-blk. However, the virtio-blk
> disk may report max discard segment as 1, at least that is exactly what
> qemu is doing.
>
> So far, block layer switches to normal request merge if max discard segment
> limit is 1, and multiple bios can be merged to single segment. This way may
> cause memory corruption in virtblk_setup_discard_write_zeroes().
>
> Fix the issue by handling single max discard segment in straightforward
> way.
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support")
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Cc: Changpeng Liu <changpeng.liu@xxxxxxxxx>
> Cc: Daniel Verkamp <dverkamp@xxxxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
> Cc: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> ---
> drivers/block/virtio_blk.c | 31 +++++++++++++++++++++++--------
> 1 file changed, 23 insertions(+), 8 deletions(-)
Thanks for fixing this!
Stefan
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