sim-mbim: fix race condition when sync requested during preload

This is an extremely tricky race condition.

 * During SIM object initialization, we try to load SIM type (first
   item loaded).
 * MMSimMbim SIM type loading step runs preload_subscriber_info(),
   which:
   ** Sets self->priv->preload = TRUE; so that it is not run anymore.
   ** Sets the sync monitor to clear preloaded info if sync needed.
   ** Runs the subscriber ready status operation asynchronously.
   ** Just before the subscriber ready status operation returns, the
      system goes to sleep.
   ** The resume logic kicks in, and we flag the modem with sync
      needed, which clears the self->priv->preload flag.
 * Then the subscriber ready status operation response arrives, and we
   store the IMSI and the other things.
 * When the next initialization step happens, given that
   self->priv->preload is cleared, we run attempt to run
   preload_subscriber_info() again, and this time it finds the info like
   IMSI is already set, so asserts:

    0x00007cbcd287523f (libglib-2.0.so.0 - gtestutils.c: 3253)      g_assertion_message
    0x00007cbcd28752a2 (libglib-2.0.so.0 - gtestutils.c: 3279)      g_assertion_message_expr
    0x00005cbdab0a2dc0 (ModemManager - mm-sim-mbim.c: 253)  subscriber_ready_status_ready
    0x00007cbcd29a173b (libgio-2.0.so.0 - gtask.c: 1230)    g_task_return_now
    0x00007cbcd29a0799 (libgio-2.0.so.0 - gtask.c: 1300)    g_task_return
    0x00007cbcd2a548e0 (libmbim-glib.so.4 - mbim-device.c: 264)     transaction_task_complete_and_free
    0x00007cbcd2a562fc (libmbim-glib.so.4 - mbim-device.c: 1047)    data_available
    0x00007cbcd28534a6 (libglib-2.0.so.0 - gmain.c: 3417)   g_main_context_dispatch
    0x00007cbcd28537b1 (libglib-2.0.so.0 - gmain.c: 4211)   g_main_context_iterate
    0x00007cbcd2853a25 (libglib-2.0.so.0 - gmain.c: 4411)   g_main_loop_run
    0x00005cbdab034d26 (ModemManager - main.c: 217) main
    0x00007cbcd25e16c5 (libc.so.6 + 0x000286c5)     __libc_init_first
    0x00007cbcd25e1781 (libc.so.6 + 0x00028781)     __libc_start_main
    0x00005cbdab034a40 (ModemManager + 0x00061a40)  _start

In order to solve this, upon a sync request the ongoing preload
operation will be cancelled.

0 files changed, 0 insertions, 0 deletions