Panic during kernel rebuild; file system left inconsistent

[Brett Glass]

I've got a 4.9 machine that's acting as a router and is lightly loaded
otherwise. (There are a significant number of interrupts from network
interface cards at all times, but disk usage is normally quite light.) When I
typed

make depend; make; make install

to rebuild the kernel, the system had a panic during the "make" phase. Upon
rebooting, I got a message saying that there was a "unexpected softupdates
inconsistency" in /usr. After running fsck (which reported a large number of
problems), I found that all of the files in the lost+found directory were
(maybe not surprisingly) dependency files. I repeated the build, doing

nice make clean; sync; sleep 10; nice make depend; sync; ...

and this time the kernel built with no problems. I suspect (though I don't
have a backtrace) that heavily loading the file system and/or the ata driver
in the presence of many other interrupts can cause a panic which softupdates
is not prepared to handle. Have others seen this?

--Brett Glass