nbd-server: do not exit on failed memory allocation

The amount of memory allocated in nbd_co_receive_request is driven by the
NBD client (possibly a virtual machine).  Parallel I/O can cause the
server to allocate a large amount of memory; check for failures and
return ENOMEM in that case.

Cc: qemu-block@nongnu.org
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/nbd/server.c b/nbd/server.c
index c41af0debe..eead339a2c 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -836,7 +836,11 @@ static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *reque
             goto out;
         }
 
-        req->data = blk_blockalign(client->exp->blk, request->len);
+        req->data = blk_try_blockalign(client->exp->blk, request->len);
+        if (req->data == NULL) {
+            rc = -ENOMEM;
+            goto out;
+        }
     }
     if (command == NBD_CMD_WRITE) {
         TRACE("Reading %u byte(s)", request->len);