From: Dongli Zhang <dongli.zh...@oracle.com> [ Upstream commit 8130b9d5b5abf26f9927b487c15319a187775f34 ]
This patch adds the barrier to guarantee that req->err is always updated before req->state. Otherwise, read_reply() would not return ERR_PTR(req->err) but req->body, when process_writes()->xb_write() is failed. Signed-off-by: Dongli Zhang <dongli.zh...@oracle.com> Link: https://lore.kernel.org/r/20200303221423.21962-2-dongli.zh...@oracle.com Reviewed-by: Julien Grall <jgr...@amazon.com> Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com> Signed-off-by: Sasha Levin <sas...@kernel.org> --- drivers/xen/xenbus/xenbus_comms.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c index 852ed161fc2a7..eb5151fc8efab 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -397,6 +397,8 @@ static int process_writes(void) if (state.req->state == xb_req_state_aborted) kfree(state.req); else { + /* write err, then update state */ + virt_wmb(); state.req->state = xb_req_state_got_reply; wake_up(&state.req->wq); } -- 2.20.1 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
