Kernel stack can be swapped. This means that stuff that's on the stack

should never be referenced outside the context of the process to which
this stack belongs unless we do the PHOLD/PRELE dance. Loads of code
doesn't follow the rules here. Instead of trying to track down all
offenders and fix this hairy situation, it makes much more sense
to not swap kernel stacks.

From art@, tested by many some time ago.

6 files changed, 8 insertions, 22 deletions

diff --git a/sys/arch/alpha/alpha/pmap.c b/sys/arch/alpha/alpha/pmap.c
index bd49bee76d3..f39ff355ac1 100644
--- a/sys/arch/alpha/alpha/pmap.c
+++ b/sys/arch/alpha/alpha/pmap.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pmap.c,v 1.47 2006/04/13 14:41:08 brad Exp $ */
+/* $OpenBSD: pmap.c,v 1.48 2006/11/29 12:24:15 miod Exp $ */
 /* $NetBSD: pmap.c,v 1.154 2000/12/07 22:18:55 thorpej Exp $ */
 
 /*-
@@ -2867,9 +2867,8 @@ pmap_emulate_reference(struct proc *p, vaddr_t v, int user, int type)
 		panic("pmap_emulate_reference: invalid pte");
 #if 0
 	/*
-	 * Can't do these, because cpu_fork and cpu_swapin call
-	 * pmap_emulate_reference(), and the bits aren't guaranteed,
-	 * for them...
+	 * Can't do these, because cpu_fork call pmap_emulate_reference(),
+	 * and the bits aren't guaranteed, for them...
 	 */
 	if (type == ALPHA_MMCSR_FOW) {
 		if (!(*pte & (user ? PG_UWE : PG_UWE | PG_KWE)))
diff --git a/sys/arch/amd64/amd64/fpu.c b/sys/arch/amd64/amd64/fpu.c
index e2dd39a2d31..cc19b095f2d 100644
--- a/sys/arch/amd64/amd64/fpu.c
+++ b/sys/arch/amd64/amd64/fpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpu.c,v 1.11 2006/04/19 15:51:22 mickey Exp $	*/
+/*	$OpenBSD: fpu.c,v 1.12 2006/11/29 12:24:17 miod Exp $	*/
 /*	$NetBSD: fpu.c,v 1.1 2003/04/26 18:39:28 fvdl Exp $	*/
 
 /*-
@@ -301,7 +301,6 @@ fpusave_proc(struct proc *p, int save)
 	struct cpu_info *oci;
 
 	KDASSERT(p->p_addr != NULL);
-	KDASSERT(p->p_flag & P_INMEM);
 
 	oci = p->p_addr->u_pcb.pcb_fpcpu;
 	if (oci == NULL)
diff --git a/sys/arch/arm/arm/db_trace.c b/sys/arch/arm/arm/db_trace.c
index 00206ef7efc..1f82b9420f8 100644
--- a/sys/arch/arm/arm/db_trace.c
+++ b/sys/arch/arm/arm/db_trace.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: db_trace.c,v 1.2 2004/05/19 03:17:07 drahn Exp $	*/
+/*	$OpenBSD: db_trace.c,v 1.3 2006/11/29 12:24:17 miod Exp $	*/
 /*	$NetBSD: db_trace.c,v 1.8 2003/01/17 22:28:48 thorpej Exp $	*/
 
 /* 
@@ -113,10 +113,6 @@ db_stack_trace_print(addr, have_addr, count, modif, pr)
 				(*pr)("not found\n");
 				return;
 			}	
-			if (!(p->p_flag & P_INMEM)) {
-				(*pr)("swapped out\n");
-				return;
-			}
 			u = p->p_addr;
 #ifdef acorn26
 			frame = (u_int32_t *)(u->u_pcb.pcb_sf->sf_r11);
diff --git a/sys/arch/sparc/dev/fd.c b/sys/arch/sparc/dev/fd.c
index 3642726a299..9f1977266a1 100644
--- a/sys/arch/sparc/dev/fd.c
+++ b/sys/arch/sparc/dev/fd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fd.c,v 1.45 2006/09/26 23:33:04 krw Exp $	*/
+/*	$OpenBSD: fd.c,v 1.46 2006/11/29 12:24:17 miod Exp $	*/
 /*	$NetBSD: fd.c,v 1.51 1997/05/24 20:16:19 pk Exp $	*/
 
 /*-
@@ -1895,7 +1895,6 @@ fdformat(dev, finfo, p)
 	if (bp == 0)
 		return (ENOBUFS);
 
-	PHOLD(p);
 	bzero((void *)bp, sizeof(struct buf));
 	bp->b_flags = B_BUSY | B_PHYS | B_FORMAT;
 	bp->b_proc = p;
@@ -1942,7 +1941,6 @@ fdformat(dev, finfo, p)
 
 	/* ...and wait for it to complete */
 	rv = biowait(bp);
-	PRELE(p);
 	free(bp, M_TEMP);
 	return (rv);
 }
diff --git a/sys/arch/sparc64/dev/fd.c b/sys/arch/sparc64/dev/fd.c
index 04f71364c2c..2aaa9286441 100644
--- a/sys/arch/sparc64/dev/fd.c
+++ b/sys/arch/sparc64/dev/fd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fd.c,v 1.7 2006/09/26 23:33:04 krw Exp $	*/
+/*	$OpenBSD: fd.c,v 1.8 2006/11/29 12:24:17 miod Exp $	*/
 /*	$NetBSD: fd.c,v 1.112 2003/08/07 16:29:35 agc Exp $	*/
 
 /*-
@@ -1944,7 +1944,6 @@ fdformat(dev, finfo, p)
 	if (bp == NULL)
 		return (ENOBUFS);
 
-	PHOLD(p);
 	bzero((void *)bp, sizeof(struct buf));
 	bp->b_flags = B_BUSY | B_PHYS | B_FORMAT;
 	bp->b_proc = p;
@@ -1991,7 +1990,6 @@ fdformat(dev, finfo, p)
 
 	/* ...and wait for it to complete */
 	rv = biowait(bp);
-	PRELE(p);
 	free(bp, M_TEMP);
 	return (rv);
 }
diff --git a/sys/arch/sparc64/sparc64/db_trace.c b/sys/arch/sparc64/sparc64/db_trace.c
index dd25eee69f2..2bb07cffee2 100644
--- a/sys/arch/sparc64/sparc64/db_trace.c
+++ b/sys/arch/sparc64/sparc64/db_trace.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: db_trace.c,v 1.7 2002/10/09 21:10:48 deraadt Exp $	*/
+/*	$OpenBSD: db_trace.c,v 1.8 2006/11/29 12:24:17 miod Exp $	*/
 /*	$NetBSD: db_trace.c,v 1.23 2001/07/10 06:06:16 eeh Exp $ */
 
 /*
@@ -87,10 +87,6 @@ db_stack_trace_print(addr, have_addr, count, modif, pr)
 				(*pr)("not found\n");
 				return;
 			}	
-			if ((p->p_flag & P_INMEM) == 0) {
-				(*pr)("swapped out\n");
-				return;
-			}
 			u = p->p_addr;
 			frame = (vaddr_t)u->u_pcb.pcb_sp;
 			(*pr)("at %p\n", frame);