[SUMMARY] kernel patches - what if?

From: The Hermit Hacker (scrappy@hub.org)
Date: Tue Jun 17 1997 - 19:30:59 CDT

I got a couple of answers on this, some that didn't seem to pertain to
Solaris, but to SunOS...but thanks for all the responses. There were
alot of "I don't know, but would like to know" answers...which, to me,
isn't good, except that it tends to mean that ppl just haven't hit the
problem before (ie. patches are generally safe to apply)

Included below is the original question, plus the two responses that seemed
relevant enough to the question (ie. Solaris vs SunOS specific)

>> I'm currently patching up a few of the older Sun/Sparc's on our
>>network, and wonder if anyone can tell me what the procedure is if a kernel
>>patch causes a machine *not* to boot? How do I get at the old kernel so that
>>I can do a 'backoutpatch'?
>> I know under SunOS 4.x.x, the kernel was /vmunix, and you just booted
>>/vmunix.old if the boot failed...but I can't find similar under Solaris.
>>Marc G. Fournier scrappy@hub.org
>>Systems Administrator @ hub.org scrappy@freebsd.org

Boot single-user mode from cdrom
Mount the boot partition to the cdrom partition /a
copy /platform/sun4?/kernel/unix /a/platform/sun4?/kernel/unix

To prevent this in the future, copy /platform/sun4?/kernel/unix
to /platform/sun4?/kernel/unix.backup
That way, during boot up you can specify that backup file.

Of course, substitute the ? above for c,m,or u, which ever
is appropriate.


From: Cagri Yucel <cyucel@is.ku.edu.tr>

Well, did you do this ? or asking just for incase ? if so copy kernel and
genunix as .olds. If something goes wrong simply do a boot -ar, so prom
will ask you every kernel file to be loaded.



Marc G. Fournier
Systems Administrator @ hub.org
primary: scrappy@hub.org secondary: scrappy@{freebsd|postgresql}.org

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