[Qemu-devel] RFC: exit on incoming exec migrate failure

[Andrew Farmer]

Right now, if an incoming migrate through exec fails, the qemu process will end 
up chewing CPU indefinitely - it looks like it closes the migration FD but 
doesn't remove its IO handler properly. An easy way to reproduce this is to try 
launching with -incoming exec:/bin/false. This is obviously useless, but 
illustrates the issue handily.

One solution might be to retry the command on migrate failure, but that won't 
really help in all circumstances (for instance, if the migration command is 
broken!), so it seems equally appropriate to just die if an incoming exec 
migration fails. The patch is trivial, and follows - does this look sensible? 
(I'm new to qemu development, but trying to pick it up.)

diff --git a/migration-exec.c b/migration-exec.c
index c830669..0292c19 100644
--- a/migration-exec.c
+++ b/migration-exec.c
@@ -114,7 +114,7 @@ static void exec_accept_incoming_migration(void *opaque)
     ret = qemu_loadvm_state(f);
     if (ret < 0) {
         fprintf(stderr, "load of migration failed\n");
-        goto err;
+        exit(0);
     }
     qemu_announce_self();
     dprintf("successfully loaded vm state\n");
@@ -123,7 +123,6 @@ static void exec_accept_incoming_migration(void *opaque)
     if (autostart)
         vm_start();
 
-err:
     qemu_fclose(f);
 }