From: utzoo!decvax!harpo!ihnp4!ixn5c!inuxc!pur-ee!ecn-pa:bruner
Newsgroups: net.unix-wizards
Title: Re: csv versus csav
Article-I.D.: ecn-pa.657
Posted: Wed Nov 24 20:03:21 1982
Received: Thu Nov 25 11:02:48 1982
References: sri-unix.4356 rabbit.934

The "csv" signal bug can cause unexpected bus errors or memory faults
in programs that use setjmp/longjmp.  Suppose that function X calls
"setjmp", then calls function Y, which calls other things.  When
a signal is received, the signal processing function Z is called.
Suppose Z calls "longjmp".  "longjmp" traces back through the stack
frames to find the stack frame for Y (this contains R2,R3,R4 from X)
and returns to X.  If the signal was received right after a
"jsr r5,csv" (before R5 is changed to point to the new stack frame)
then R5 contains a text address (or, if it is separated I/D, a
possibly-nonexistant data address), and the stack traceback will
eventually go out of bounds (memory fault) or encounter an odd
address (bus error).

--John Bruner