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[src/trunk]: src/sys - Only increment nprocs when we're creating a new proces...



details:   https://anonhg.NetBSD.org/src/rev/4839670fd48f
branches:  trunk
changeset: 1009297:4839670fd48f
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sun Apr 19 20:31:59 2020 +0000

description:
- Only increment nprocs when we're creating a new process, not just
  when allocating a PID.
- Per above, proc_free_pid() no longer decrements nprocs.  It's now done
  in proc_free() right after proc_free_pid().
- Ensure nprocs is accessed using atomics everywhere.

diffstat:

 sys/compat/linux/common/linux_misc.c        |   6 +++---
 sys/compat/linux/common/linux_sched.c       |  16 +++-------------
 sys/compat/linux32/common/linux32_sysinfo.c |   6 +++---
 sys/compat/netbsd32/netbsd32_execve.c       |   5 +++--
 sys/kern/kern_exec.c                        |   9 +++++++--
 sys/kern/kern_exit.c                        |   5 +++--
 sys/kern/kern_proc.c                        |   6 ++----
 sys/miscfs/procfs/procfs_linux.c            |   6 +++---
 sys/miscfs/procfs/procfs_vfsops.c           |  10 +++++-----
 sys/rump/librump/rumpkern/lwproc.c          |   7 ++++---
 10 files changed, 36 insertions(+), 40 deletions(-)

diffs (truncated from 309 to 300 lines):

diff -r a0fd1886f6b7 -r 4839670fd48f sys/compat/linux/common/linux_misc.c
--- a/sys/compat/linux/common/linux_misc.c      Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/compat/linux/common/linux_misc.c      Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_misc.c,v 1.247 2019/12/31 13:07:13 ad Exp $      */
+/*     $NetBSD: linux_misc.c,v 1.248 2020/04/19 20:31:59 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1995, 1998, 1999, 2008 The NetBSD Foundation, Inc.
@@ -57,7 +57,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_misc.c,v 1.247 2019/12/31 13:07:13 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_misc.c,v 1.248 2020/04/19 20:31:59 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1360,7 +1360,7 @@
        si.totalswap = (u_long)uvmexp.swpages * uvmexp.pagesize;
        si.freeswap = 
            (u_long)(uvmexp.swpages - uvmexp.swpginuse) * uvmexp.pagesize;
-       si.procs = nprocs;
+       si.procs = atomic_load_relaxed(&nprocs);
 
        /* The following are only present in newer Linux kernels. */
        si.totalbig = 0;
diff -r a0fd1886f6b7 -r 4839670fd48f sys/compat/linux/common/linux_sched.c
--- a/sys/compat/linux/common/linux_sched.c     Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/compat/linux/common/linux_sched.c     Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_sched.c,v 1.73 2019/11/23 19:42:52 ad Exp $      */
+/*     $NetBSD: linux_sched.c,v 1.74 2020/04/19 20:31:59 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1999, 2019 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.73 2019/11/23 19:42:52 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.74 2020/04/19 20:31:59 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -182,7 +182,7 @@
        void *parent_tidptr, *tls, *child_tidptr;
        vaddr_t uaddr;
        lwpid_t lid;
-       int flags, tnprocs, error;
+       int flags, error;
 
        p = l->l_proc;
        flags = SCARG(uap, flags);
@@ -190,17 +190,8 @@
        tls = SCARG(uap, tls);
        child_tidptr = SCARG(uap, child_tidptr);
 
-       tnprocs = atomic_inc_uint_nv(&nprocs);
-       if (__predict_false(tnprocs >= maxproc) ||
-           kauth_authorize_process(l->l_cred, KAUTH_PROCESS_FORK, p,
-           KAUTH_ARG(tnprocs), NULL, NULL) != 0) {
-               atomic_dec_uint(&nprocs);
-               return EAGAIN;
-       }
-
        uaddr = uvm_uarea_alloc();
        if (__predict_false(uaddr == 0)) {
-               atomic_dec_uint(&nprocs);
                return ENOMEM;
        }
 
@@ -209,7 +200,6 @@
            &l->l_sigmask, &l->l_sigstk);
        if (__predict_false(error)) {
                DPRINTF(("%s: lwp_create error=%d\n", __func__, error));
-               atomic_dec_uint(&nprocs);
                uvm_uarea_free(uaddr);
                return error;
        }
diff -r a0fd1886f6b7 -r 4839670fd48f sys/compat/linux32/common/linux32_sysinfo.c
--- a/sys/compat/linux32/common/linux32_sysinfo.c       Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/compat/linux32/common/linux32_sysinfo.c       Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux32_sysinfo.c,v 1.10 2019/12/31 13:07:13 ad Exp $ */
+/*     $NetBSD: linux32_sysinfo.c,v 1.11 2020/04/19 20:31:59 thorpej Exp $ */
 
 /*-
  * Copyright (c) 2006 Emmanuel Dreyfus, all rights reserved.
@@ -33,7 +33,7 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(0, "$NetBSD: linux32_sysinfo.c,v 1.10 2019/12/31 13:07:13 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux32_sysinfo.c,v 1.11 2020/04/19 20:31:59 thorpej Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -83,7 +83,7 @@
        si.totalswap = (u_long)uvmexp.swpages * uvmexp.pagesize;
        si.freeswap = 
            (u_long)(uvmexp.swpages - uvmexp.swpginuse) * uvmexp.pagesize;
-       si.procs = nprocs;
+       si.procs = atomic_load_relaxed(&nprocs);
 
        /* The following are only present in newer Linux kernels. */
        si.totalbig = 0;
diff -r a0fd1886f6b7 -r 4839670fd48f sys/compat/netbsd32/netbsd32_execve.c
--- a/sys/compat/netbsd32/netbsd32_execve.c     Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/compat/netbsd32/netbsd32_execve.c     Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: netbsd32_execve.c,v 1.41 2019/09/17 15:19:27 christos Exp $    */
+/*     $NetBSD: netbsd32_execve.c,v 1.42 2020/04/19 20:31:59 thorpej Exp $     */
 
 /*
  * Copyright (c) 1998, 2001 Matthew R. Green
@@ -28,7 +28,7 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(0, "$NetBSD: netbsd32_execve.c,v 1.41 2019/09/17 15:19:27 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: netbsd32_execve.c,v 1.42 2020/04/19 20:31:59 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -182,6 +182,7 @@
        rlim_t max_fileactions;
        proc_t *p = l->l_proc;
 
+       /* check_posix_spawn() increments nprocs for us. */
        error = check_posix_spawn(l);
        if (error) {
                *retval = error;
diff -r a0fd1886f6b7 -r 4839670fd48f sys/kern/kern_exec.c
--- a/sys/kern/kern_exec.c      Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/kern/kern_exec.c      Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_exec.c,v 1.496 2020/04/14 22:42:18 kamil Exp $    */
+/*     $NetBSD: kern_exec.c,v 1.497 2020/04/19 20:31:59 thorpej Exp $  */
 
 /*-
  * Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.496 2020/04/14 22:42:18 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.497 2020/04/19 20:31:59 thorpej Exp $");
 
 #include "opt_exec.h"
 #include "opt_execfmt.h"
@@ -2397,6 +2397,10 @@
        return error;
 }
 
+/*
+ * N.B. increments nprocs upon success.  Callers need to drop nprocs if
+ * they fail for some other reason.
+ */
 int
 check_posix_spawn(struct lwp *l1)
 {
@@ -2751,6 +2755,7 @@
        rlim_t max_fileactions;
        proc_t *p = l1->l_proc;
 
+       /* check_posix_spawn() increments nprocs for us. */
        error = check_posix_spawn(l1);
        if (error) {
                *retval = error;
diff -r a0fd1886f6b7 -r 4839670fd48f sys/kern/kern_exit.c
--- a/sys/kern/kern_exit.c      Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/kern/kern_exit.c      Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_exit.c,v 1.287 2020/04/04 20:20:12 thorpej Exp $  */
+/*     $NetBSD: kern_exit.c,v 1.288 2020/04/19 20:31:59 thorpej Exp $  */
 
 /*-
  * Copyright (c) 1998, 1999, 2006, 2007, 2008, 2020 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.287 2020/04/04 20:20:12 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.288 2020/04/19 20:31:59 thorpej Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_dtrace.h"
@@ -1216,6 +1216,7 @@
         * Let pid be reallocated.
         */
        proc_free_pid(p->p_pid);
+       atomic_dec_uint(&nprocs);
 
        /*
         * Unlink process from its process group.
diff -r a0fd1886f6b7 -r 4839670fd48f sys/kern/kern_proc.c
--- a/sys/kern/kern_proc.c      Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/kern/kern_proc.c      Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_proc.c,v 1.243 2020/04/06 08:20:05 kamil Exp $    */
+/*     $NetBSD: kern_proc.c,v 1.244 2020/04/19 20:31:59 thorpej Exp $  */
 
 /*-
  * Copyright (c) 1999, 2006, 2007, 2008, 2020 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.243 2020/04/06 08:20:05 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.244 2020/04/19 20:31:59 thorpej Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_kstack.h"
@@ -866,8 +866,6 @@
                last_free_pt = pid;
                pid_alloc_cnt--;
        }
-
-       atomic_dec_uint(&nprocs);
 }
 
 void
diff -r a0fd1886f6b7 -r 4839670fd48f sys/miscfs/procfs/procfs_linux.c
--- a/sys/miscfs/procfs/procfs_linux.c  Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/miscfs/procfs/procfs_linux.c  Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: procfs_linux.c,v 1.80 2020/01/02 15:42:27 thorpej Exp $      */
+/*      $NetBSD: procfs_linux.c,v 1.81 2020/04/19 20:31:59 thorpej Exp $      */
 
 /*
  * Copyright (c) 2001 Wasabi Systems, Inc.
@@ -36,7 +36,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: procfs_linux.c,v 1.80 2020/01/02 15:42:27 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: procfs_linux.c,v 1.81 2020/04/19 20:31:59 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -346,7 +346,7 @@
                (int)(averunnable.ldavg[2] / averunnable.fscale),
                (int)(averunnable.ldavg[2] * 100 / averunnable.fscale % 100),
                1,              /* number of ONPROC processes */
-               nprocs,
+               atomic_load_relaxed(&nprocs),
                30000);         /* last pid */
        if (len == 0)
                goto out;
diff -r a0fd1886f6b7 -r 4839670fd48f sys/miscfs/procfs/procfs_vfsops.c
--- a/sys/miscfs/procfs/procfs_vfsops.c Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/miscfs/procfs/procfs_vfsops.c Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: procfs_vfsops.c,v 1.104 2020/04/04 20:49:30 ad Exp $   */
+/*     $NetBSD: procfs_vfsops.c,v 1.105 2020/04/19 20:31:59 thorpej Exp $      */
 
 /*
  * Copyright (c) 1993
@@ -76,7 +76,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: procfs_vfsops.c,v 1.104 2020/04/04 20:49:30 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: procfs_vfsops.c,v 1.105 2020/04/19 20:31:59 thorpej Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_compat_netbsd.h"
@@ -236,9 +236,9 @@
        sbp->f_frsize = PAGE_SIZE;
        sbp->f_iosize = PAGE_SIZE;
        sbp->f_blocks = 1;
-       sbp->f_files = maxproc;                 /* approx */
-       sbp->f_ffree = maxproc - nprocs;        /* approx */
-       sbp->f_favail = maxproc - nprocs;       /* approx */
+       sbp->f_files = maxproc;                                 /* approx */
+       sbp->f_ffree = maxproc - atomic_load_relaxed(&nprocs);  /* approx */
+       sbp->f_favail = maxproc - atomic_load_relaxed(&nprocs); /* approx */
 
        return (0);
 }
diff -r a0fd1886f6b7 -r 4839670fd48f sys/rump/librump/rumpkern/lwproc.c
--- a/sys/rump/librump/rumpkern/lwproc.c        Sun Apr 19 20:07:53 2020 +0000
+++ b/sys/rump/librump/rumpkern/lwproc.c        Sun Apr 19 20:31:59 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: lwproc.c,v 1.44 2020/02/15 18:12:15 ad Exp $  */
+/*      $NetBSD: lwproc.c,v 1.45 2020/04/19 20:32:00 thorpej Exp $     */
 
 /*
  * Copyright (c) 2010, 2011 Antti Kantee.  All Rights Reserved.
@@ -28,7 +28,7 @@
 #define RUMP__CURLWP_PRIVATE
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.44 2020/02/15 18:12:15 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.45 2020/04/19 20:32:00 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -178,7 +178,8 @@



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