Comment 22 for bug 1191580

This is caused by a race condition between the two bitmap file enumeration passes in log_online_setup_bitmap_file_range(). If the 1st bitmap file in the range is deleted at that point, then the debug build will crash as reported on this bug. If the 2nd or subsequent bitmap file is deleted, the debug build will crash at ut_ad(bitmap_files->files[i].seq_num > bitmap_files->files[i - 1].seq_num) a few lines below.

For release builds this is not an issue as missing bitmap files will be detected and diagnosed on their open attempts, as fixed by bug 1179974. The current bug shows that the fix for the latter was incomplete.

This code is shared with XtraBackup thus at least theoretically (haven't checked) the issue might appear there as well.