Hello,

In my understanding the reason why texec had to be static was
because the struct member ioact was never initialised.
The call tree is execute() -> comexec() -> exchild() -> execute()
and a fork happens in exchild().
The second execute() dereferences t->ioact on line 115 which causes
SEGV. Setting ioact to NULL explicitly seems better than
doing this via "static".
Does this work for you?

- Michael


Index: exec.c
===================================================================
RCS file: /cvs/src/bin/ksh/exec.c,v
retrieving revision 1.68
diff -u -p -u -r1.68 exec.c
--- exec.c      11 Dec 2016 17:49:19 -0000      1.68
+++ exec.c      18 Dec 2017 07:05:47 -0000
@@ -409,7 +409,7 @@ comexec(struct op *t, struct tbl *volati
        volatile int rv = 0;
        char *cp;
        char **lastp;
-       static struct op texec; /* Must be static (XXX but why?) */
+       struct op texec;
        int type_flags;
        int keepasn_ok;
        int fcflags = FC_BI|FC_FUNC|FC_PATH;
@@ -688,6 +688,7 @@ comexec(struct op *t, struct tbl *volati
                texec.left = t; /* for tprint */
                texec.str = tp->val.s;
                texec.args = ap;
+               texec.ioact = NULL;
                rv = exchild(&texec, flags, xerrok, -1);
                break;
        }

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