Does 6.5 kernel require different userspace to 6.4 kernel?

[Chris Rankin]

Hi,

I have a truly ancient i586/UP/32 bit PC (for historical reasons) that
happily runs Linux 6.4.16. However, when I tried to upgrade it today
to run Linux 6.5.13, I discovered that both its console and its
networking froze almost immediately after it had booted. There is no
sign of any oops in any of the logs. My first thought was that memory
corruption had crashed the kernel, except that the SysRq interface
still works correctly.

The PC's userspace has not changed at all; I have only upgraded its
kernel from 6.4.16 to 6.5.13. And restoring the 6.4.16 kernel restores
correct operation. However, I cannot identify any clue as to what
could be wrong with my 6.5.13 kernel. Can anyone suggest anything that
may have changed between 6.4 and 6.5 that could be causing this
please?

Thanks for any assistance,
Cheers,
Chris