- Add a mutex to the proc structure p_mtx that will be used to lock accesses

  to each individual proc.
- Initialize the lock during fork1(), and destroy it in wait1().

4 files changed, 4 insertions, 0 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index c6110fa..81cde0d 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -285,6 +285,7 @@ proc0_init(void *dummy __unused)
 	/*
 	 * Create process 0 (the swapper).
 	 */
+	mtx_init(&p->p_mtx, "process lock", MTX_DEF);
 	LIST_INSERT_HEAD(&allproc, p, p_list);
 	p->p_pgrp = &pgrp0;
 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 69f526c..ce3cc21 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -539,6 +539,7 @@ loop:
 			 * release while still running in process context.
 			 */
 			cpu_wait(p);
+			mtx_destroy(&p->p_mtx);
 			zfree(proc_zone, p);
 			nprocs--;
 			return (0);
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 6caa1d2..6d9c6c1 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -367,6 +367,7 @@ again:
 	bcopy(&p1->p_startcopy, &p2->p_startcopy,
 	    (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy));
 
+	mtx_init(&p2->p_mtx, "process lock", MTX_DEF);
 	p2->p_aioinfo = NULL;
 
 	/*
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 562dd09..1cb164b 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -193,6 +193,7 @@ struct	proc {
 	struct	vnode *p_textvp;	/* Vnode of executable. */
 
 	char	p_lock;			/* Process lock (prevent swap) count. */
+	struct	mtx p_mtx;		/* Process stucture lock.  */
 	u_char	p_oncpu;		/* Which cpu we are on */
 	u_char	p_lastcpu;		/* Last cpu we were on */
 	char	p_rqindex;		/* Run queue index */