there is lprocfs_stats_collect() vs obd cleanup releasing stats data.
here is an example of failed test: https://testing.hpdd.intel.com/test_sessions/7e3c0fec-5aae-403f-94fa-4a58e111eb35
there are few more.
https://review.whamcloud.com/#/c/30432/ solves one case using RCU, but there are few others like jobstats. it's relatively easy to fix when file_operations declared explicitly, but it's not clear how to fix in other cases like LPROC_SEQ_FOPS_RW_TYPE(osc, import);