I was running the CONFIG from WT-9584 on the mirror branch and hit a segfault failure. This is NOT tcmalloc related as I am not using it, nor any system scripts that would set it. I'm just using my own script that starts up 5x parallel jobs.

The stack and error is interesting:

Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007fb8c0c72d89 in __wt_page_inmem (session=0x1d4bc80, 
    ref=0x7fb83f581f90, image=0x0, flags=8, pagep=0x7fb8a27fb348, 
    preparedp=0x7fb8a27fb33a) at ../src/btree/bt_page.c:357
357	    switch (dsk->type) {

I will put more details in as a comment.