On 10/28/2011 11:59 AM, Luiz Capitulino wrote:
A simple migration reproduces it:

1. Start the source VM with:

    # qemu [...] -S

2. Start the destination VM with:

    # qemu<source VM cmd-line>  -incoming tcp:0:4444

3. In the source VM:

    (qemu) migrate -d tcp:0:4444

4. The source VM will segfault as soon as migration completes (might not
    happen in the first try)

What is happening here is that qemu_file_put_notify() can end up closing
's->file' (in which case it's also set to NULL). The call stack is rather
complex, but Eduardo helped tracking it to:

select loop ->  migrate_fd_put_notify() ->  qemu_file_put_notify() ->
buffered_put_buffer() ->  migrate_fd_put_ready() ->
migrate_fd_completed() ->  migrate_fd_cleanup().

To be honest, it's not completely clear to me in which cases 's->file'
is not closed (on error maybe)? But I doubt this fix will make anything
worse.

Reviewed-by: Paolo Bonzini<pbonz...@redhat.com>
Acked-by: Eduardo Habkost<ehabk...@redhat.com>
Signed-off-by: Luiz Capitulino<lcapitul...@redhat.com>

Applied.  Thanks.

Regards,

Anthony Liguori

---

V2: better commit log

  migration.c |    2 +-
  1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/migration.c b/migration.c
index bdca72e..f6e6208 100644
--- a/migration.c
+++ b/migration.c
@@ -252,7 +252,7 @@ static void migrate_fd_put_notify(void *opaque)

      qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
      qemu_file_put_notify(s->file);
-    if (qemu_file_get_error(s->file)) {
+    if (s->file&&  qemu_file_get_error(s->file)) {
          migrate_fd_error(s);
      }
  }


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