While searching why files <= 700 bytes would be corrupted in our HPC environment, I discovered that they are not only “corrupted”, but contain parts of the memory.
In short, a user can create a very simple loop in a shell script and harvest whatever random data in memory.
The issue seems to be related to the rpcrdma module. Servers running with xprtrdma have not such security issue.
I can reproduce this bug in every server running CentOS >= 7.7.
Linux 3.10.0-1160.53.1.el7.x86_64 x86_64
CentOS Linux release 7.9.2009 (Core)