x86: WARNING: kernel stack frame pointer in kworker has bad value

[Dmitry Vyukov]

Hello,

I am getting the following warnings while running syzkaller fuzzer on
7a308bb3016f57e5be11a677d15b821536419d36:

WARNING: kernel stack frame pointer at ffff880065f7fef8 in
kworker/1:3:21075 has bad value ffffffff81598080
unwind stack type:0 next_sp:          (null) mask:2 graph_idx:0
...

Here are 4 examples:

https://gist.githubusercontent.com/dvyukov/7258fca11e5c3db6e8f8fb684e6168ff/raw/2ca14f3c7294c7e466611f8ecfb3072c676a657c/gistfile1.txt
https://gist.githubusercontent.com/dvyukov/cc442b144ae712f0e1bdeb065085e36a/raw/f713cef7e9689914fc94838a0a7d4192224fb6d2/gistfile1.txt
https://gist.githubusercontent.com/dvyukov/9058cce2647e3d37157c283c6400498c/raw/7a8ec8d71b9e95eeb24156073eeef96ba61d95ea/gistfile1.txt
https://gist.githubusercontent.com/dvyukov/b899dfa72d611b511a674b63676921f3/raw/90203ed26b6674dedba8c1c16dd76309ef21fbea/gistfile1.txt

Unfortunately this is not reproducible, but there is a stack dump, so
maybe it's enough to figure out the root cause.

Thanks