Summary: u-area

From: Robert M. Kuhn (
Date: Fri May 29 1992 - 12:17:40 CDT

My original query:

>vmunix: panic: error in swapping in u-area
>Could someone interpret this for me, and point me to a source for such
>For reference, this is one of 2 kernel error messages possible,
>the other being
>error in swapping out u-area

I got many replies, most pointing the finger at the creation of a swap
file with mkfile (possibly the -n option, possibly permissions). This
machine swaps to the b partition of its local disk only. Of the remaining
replies, most suggested disk failures (either overlapping partitions,
or disk errors). One system manager associated this error with problems
with tcsh. Noone pointed me to documentation. Here's Hal Stern's reply:

From: stern@sunne.East.Sun.COM (Hal Stern - NE Area Systems Engineer)

when a process gets swapped out, the user area (u area) goes
along with it. the u area contains various user-level things
of interest about the process, none of which the kernel needs
to manage the process while it is swapped (things like stack, page
table entries, system call args, etc).

if you get an error while swapping it, it could be that (a) you
have a disk failure or disk in death throes or (b) you're swapping
to a file that you created with mkfile -n, and you're out of
disk space


Thanks to (Ravi Kagalavadi - 59112)
"Anthony A. Datri" <> (Daniel Strick) (Abdi M. Oday)
Michael.Meyers@Corp.Sun.COM (Michael Meyers) (Marc Wiz) (HAO Computer System Managment Group)
Peter Shipley <shipley@tfs.COM>
Jeff Bacon <> (Russ Poffenberger) (W. Scott Lippold/CAD) (Carlo L. Tiana) (Marty Gelfand)
stern@sunne.East.Sun.COM (Hal Stern - NE Area Systems Engineer)

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