| Message ID | 20171215115123.12959-1-dgilbert@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | migration: Guard ram_bytes_remaining against early call | expand |
On Fri, Dec 15, 2017 at 11:51:23AM +0000, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Calling ram_bytes_remaining during the early part of setup is unsafe > because the ram_state isn't yet initialised. > > This can happen in the sequence: > migrate > migrate_cancel > info migrate > > if the migrate sticks trying to connect (e.g. to an unresponsive > destination due to the connect timeout). Here 'info migrate' sees > a state of CANCELLING and so assumes the migrate has partially happened. > > partial fix for: > RH bz: https://bugzilla.redhat.com/show_bug.cgi?id=1525899 > Reported-by: Xianxian Wang <xianwang@redhat.com> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Now we fetch this as long as !COMPLETE: if (s->state != MIGRATION_STATUS_COMPLETED) { info->ram->remaining = ram_bytes_remaining(); info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate; } Maybe we should also narrow this down some day. Thanks,
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Calling ram_bytes_remaining during the early part of setup is unsafe > because the ram_state isn't yet initialised. > > This can happen in the sequence: > migrate > migrate_cancel > info migrate > > if the migrate sticks trying to connect (e.g. to an unresponsive > destination due to the connect timeout). Here 'info migrate' sees > a state of CANCELLING and so assumes the migrate has partially happened. > > partial fix for: > RH bz: https://bugzilla.redhat.com/show_bug.cgi?id=1525899 > Reported-by: Xianxian Wang <xianwang@redhat.com> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com>
diff --git a/migration/ram.c b/migration/ram.c index 021d583b9b..cb1950f3eb 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -237,7 +237,8 @@ static RAMState *ram_state; uint64_t ram_bytes_remaining(void) { - return ram_state->migration_dirty_pages * TARGET_PAGE_SIZE; + return ram_state ? (ram_state->migration_dirty_pages * TARGET_PAGE_SIZE) : + 0; } MigrationStats ram_counters;