[src/trunk]: src/sys/arch/usermode Cleanup stack allocation and freeing. This...

[reinoud <reinoud%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/02bbdd5a90ab
branches:  trunk
changeset: 772506:02bbdd5a90ab
user:      reinoud <reinoud%NetBSD.org@localhost>
date:      Fri Jan 06 12:54:59 2012 +0000

description:
Cleanup stack allocation and freeing. This means the memory leak on lwp
destruction ought to be solved.

diffstat:

 sys/arch/usermode/dev/cpu.c     |  46 +++++++++++++++++++---------------------
 sys/arch/usermode/include/pcb.h |   7 ++++-
 2 files changed, 27 insertions(+), 26 deletions(-)

diffs (152 lines):

diff -r 24ab7fa9b277 -r 02bbdd5a90ab sys/arch/usermode/dev/cpu.c
--- a/sys/arch/usermode/dev/cpu.c       Fri Jan 06 12:53:07 2012 +0000
+++ b/sys/arch/usermode/dev/cpu.c       Fri Jan 06 12:54:59 2012 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.c,v 1.61 2012/01/04 15:18:57 reinoud Exp $ */
+/* $NetBSD: cpu.c,v 1.62 2012/01/06 12:54:59 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2007 Jared D. McNeill <jmcneill%invisible.ca@localhost>
@@ -30,7 +30,7 @@
 #include "opt_hz.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.61 2012/01/04 15:18:57 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.62 2012/01/06 12:54:59 reinoud Exp $");
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -278,22 +278,23 @@
        if (pcb == NULL)
                return;
 
-       if (pcb->pcb_needfree) {
-#if 0
-               free(pcb->pcb_ucp.uc_stack.ss_sp, M_TEMP);
+       if (pcb->pcb_stack_userland) {
+               free(pcb->pcb_stack_userland, M_TEMP);
+               pcb->pcb_stack_userland = NULL;
                pcb->pcb_ucp.uc_stack.ss_sp = NULL;
                pcb->pcb_ucp.uc_stack.ss_size = 0;
-#endif
+       }
 
-               free(pcb->pcb_syscall_ucp.uc_stack.ss_sp, M_TEMP);
+       if (pcb->pcb_stack_syscall) {
+               free(pcb->pcb_stack_syscall, M_TEMP);
                pcb->pcb_syscall_ucp.uc_stack.ss_sp = NULL;
                pcb->pcb_syscall_ucp.uc_stack.ss_size = 0;
+       }
 
-               free(pcb->pcb_pagefault_ucp.uc_stack.ss_sp, M_TEMP);
+       if (pcb->pcb_stack_pagefault) {
+               free(pcb->pcb_stack_pagefault, M_TEMP);
                pcb->pcb_pagefault_ucp.uc_stack.ss_sp = NULL;
                pcb->pcb_pagefault_ucp.uc_stack.ss_size = 0;
-
-               pcb->pcb_needfree = false;
        }
 }
 
@@ -317,7 +318,6 @@
 {
        struct pcb *pcb1 = lwp_getpcb(l1);
        struct pcb *pcb2 = lwp_getpcb(l2);
-       void *stack_ucp, *stack_syscall_ucp, *stack_pagefault_ucp;
 
 #ifdef CPU_DEBUG
        thunk_printf_debug("cpu_lwp_fork [%s/%p] -> [%s/%p] stack=%p stacksize=%d\n",
@@ -333,21 +333,20 @@
        memcpy(pcb2, pcb1, sizeof(struct pcb));
 
        stacksize = 2*PAGE_SIZE;
-       stack_ucp           = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
-       stack_syscall_ucp   = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
-       stack_pagefault_ucp = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
-       pcb2->pcb_needfree = true;
+       pcb2->pcb_stack_userland  = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
+       pcb2->pcb_stack_syscall   = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
+       pcb2->pcb_stack_pagefault = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
 
-       KASSERT(stack_ucp);
-       KASSERT(stack_syscall_ucp);
-       KASSERT(stack_pagefault_ucp);
+       KASSERT(pcb2->pcb_stack_userland);
+       KASSERT(pcb2->pcb_stack_syscall);
+       KASSERT(pcb2->pcb_stack_pagefault);
 
        if (thunk_getcontext(&pcb2->pcb_ucp))
                panic("getcontext failed");
 
        /* set up the ucontext for the userland switch */
        /* XXX BUG TODO when is this stack space freed? */
-       pcb2->pcb_ucp.uc_stack.ss_sp = stack_ucp;
+       pcb2->pcb_ucp.uc_stack.ss_sp = pcb2->pcb_stack_userland;
        pcb2->pcb_ucp.uc_stack.ss_size = stacksize;
        pcb2->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU;
        pcb2->pcb_ucp.uc_link = &pcb2->pcb_userret_ucp;
@@ -356,7 +355,7 @@
            3, &pcb2->pcb_ucp, func, arg);
 
        /* set up the ucontext for the syscall */
-       pcb2->pcb_syscall_ucp.uc_stack.ss_sp = stack_syscall_ucp;
+       pcb2->pcb_syscall_ucp.uc_stack.ss_sp = pcb2->pcb_stack_syscall;
        pcb2->pcb_syscall_ucp.uc_stack.ss_size = stacksize;
        pcb2->pcb_syscall_ucp.uc_flags = _UC_STACK | _UC_CPU;
        pcb2->pcb_syscall_ucp.uc_link = &pcb2->pcb_userret_ucp;
@@ -364,7 +363,7 @@
            0, NULL, NULL, NULL);
 
        /* set up the ucontext for the pagefault */
-       pcb2->pcb_pagefault_ucp.uc_stack.ss_sp = stack_pagefault_ucp;
+       pcb2->pcb_pagefault_ucp.uc_stack.ss_sp = pcb2->pcb_stack_pagefault;
        pcb2->pcb_pagefault_ucp.uc_stack.ss_size = stacksize;
        pcb2->pcb_pagefault_ucp.uc_flags = _UC_STACK | _UC_CPU;
        pcb2->pcb_pagefault_ucp.uc_link = &pcb2->pcb_trapret_ucp;
@@ -385,7 +384,6 @@
 {
        vaddr_t minaddr, maxaddr;
        size_t stacksize, msgbufsize = 32 * 1024;
-       void *stack_pagefault_ucp;
 
        /* get ourself a message buffer */
        um_msgbuf = kmem_zalloc(msgbufsize, KM_SLEEP);
@@ -415,9 +413,9 @@
 
        /* set up the ucontext for the pagefault */
        stacksize = 2*PAGE_SIZE;
-       stack_pagefault_ucp = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
+       lwp0pcb.pcb_stack_pagefault = malloc(stacksize, M_TEMP, M_WAITOK | M_ZERO);
 
-       lwp0pcb.pcb_pagefault_ucp.uc_stack.ss_sp = stack_pagefault_ucp;
+       lwp0pcb.pcb_pagefault_ucp.uc_stack.ss_sp = lwp0pcb.pcb_stack_pagefault;
        lwp0pcb.pcb_pagefault_ucp.uc_stack.ss_size = stacksize;
        lwp0pcb.pcb_pagefault_ucp.uc_flags = _UC_STACK | _UC_CPU;
        lwp0pcb.pcb_pagefault_ucp.uc_link = &lwp0pcb.pcb_userret_ucp;
diff -r 24ab7fa9b277 -r 02bbdd5a90ab sys/arch/usermode/include/pcb.h
--- a/sys/arch/usermode/include/pcb.h   Fri Jan 06 12:53:07 2012 +0000
+++ b/sys/arch/usermode/include/pcb.h   Fri Jan 06 12:54:59 2012 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pcb.h,v 1.15 2012/01/03 10:53:46 reinoud Exp $ */
+/* $NetBSD: pcb.h,v 1.16 2012/01/06 12:54:59 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2007 Jared D. McNeill <jmcneill%invisible.ca@localhost>
@@ -40,13 +40,16 @@
 //typedef ucontext_t trapframe;
 
 struct pcb {
+       void            *pcb_stack_userland;
+       void            *pcb_stack_syscall;
+       void            *pcb_stack_pagefault;
+
        ucontext_t       pcb_ucp;               /* lwp switchframe */
        ucontext_t       pcb_syscall_ucp;       /* syscall context */
        ucontext_t       pcb_userret_ucp;       /* return to userland context */
        ucontext_t       pcb_pagefault_ucp;     /* pagefault context */
        ucontext_t       pcb_trapret_ucp;
 
-       bool             pcb_needfree;
        void *           pcb_onfault;           /* on fault handler */
 
        int              pcb_errno;             /* save/restore place */