Function _ma_apply_undo_row_insert() (starts at line 6887 of storage/maria/ma_blockrec.c) doesn't look right. All through the function if some error condition happens it jumps to the 'err' label, but from there it jumps back to the 'end' label. And here first it calls _ma_bitmap_flushable(info, -1) which seems to be necessary only after the call to _ma_bitmap_flushable(info, 1). But jump to the 'err' label can happen before that call.
And second at the 'end' label it calls _ma_unpin_all_pages_and_finalize_row(info, lsn). But variable 'lsn' gets initialized only after 4 possible jumps to the 'err' label and I don't see a possible path inside _ma_unpin_all_pages_and_finalize_row that won't use contents of 'lsn' variable.
All this doesn't look right and needs some fixing.