Module Name: src
Committed By: riastradh
Date: Wed Sep 21 10:50:11 UTC 2022
Modified Files:
src/sys/kern: kern_crashme.c
src/sys/sys: crashme.h
Log Message:
crashme(9): Use sysctl mib numbers, not node pointers.
The node pointers are not stable across insertions of siblings,
because they are pointers into arrays that may be reallocated and
moved elsewhere.
XXX Need to audit the tree for other bugs of this class, or change
sysctl(9) so it returns stable node pointers.
To generate a diff of this commit:
cvs rdiff -u -r1.7 -r1.8 src/sys/kern/kern_crashme.c
cvs rdiff -u -r1.1 -r1.2 src/sys/sys/crashme.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_crashme.c
diff -u src/sys/kern/kern_crashme.c:1.7 src/sys/kern/kern_crashme.c:1.8
--- src/sys/kern/kern_crashme.c:1.7 Tue Aug 30 22:38:26 2022
+++ src/sys/kern/kern_crashme.c Wed Sep 21 10:50:11 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_crashme.c,v 1.7 2022/08/30 22:38:26 riastradh Exp $ */
+/* $NetBSD: kern_crashme.c,v 1.8 2022/09/21 10:50:11 riastradh Exp $ */
/*
* Copyright (c) 2018, 2019 Matthew R. Green
@@ -91,7 +91,7 @@ static crashme_node nodes[] = {
};
static crashme_node *first_node;
static kmutex_t crashme_lock;
-static const struct sysctlnode *crashme_root = NULL;
+static int crashme_root = -1;
static bool crashme_enable = 0;
/*
@@ -103,8 +103,9 @@ crashme_add(crashme_node *ncn)
int rv = -1;
crashme_node *cn;
crashme_node *last = NULL;
+ const struct sysctlnode *cnode;
- if (crashme_root == NULL)
+ if (crashme_root == -1)
return -1;
mutex_enter(&crashme_lock);
@@ -115,17 +116,16 @@ crashme_add(crashme_node *ncn)
if (!cn) {
ncn->cn_next = NULL;
- rv = sysctl_createv(NULL, 0,
- &crashme_root, &ncn->cn_sysctl,
- CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
- CTLTYPE_INT, ncn->cn_name,
- SYSCTL_DESCR(ncn->cn_longname),
- crashme_sysctl_forwarder, 0,
- NULL, 0,
- CTL_CREATE, CTL_EOL);
+ rv = sysctl_createv(NULL, 0, NULL, &cnode,
+ CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
+ CTLTYPE_INT, ncn->cn_name,
+ SYSCTL_DESCR(ncn->cn_longname),
+ crashme_sysctl_forwarder, 0, NULL, 0,
+ CTL_DEBUG, crashme_root, CTL_CREATE, CTL_EOL);
/* don't insert upon failure */
if (rv == 0) {
+ ncn->cn_sysctl = cnode->sysctl_num;
if (last)
last->cn_next = ncn;
if (first_node == NULL)
@@ -158,9 +158,9 @@ crashme_remove(crashme_node *rcn)
prev->cn_next = cn->cn_next;
if ((rv = sysctl_destroyv(NULL, CTL_DEBUG, crashme_root,
- cn->cn_name, CTL_EOL)) == 0)
+ cn->cn_sysctl, CTL_EOL)) == 0)
printf("%s: unable to remove %s from sysctl\n",
- __func__, cn->cn_name);
+ __func__, cn->cn_name);
break;
}
mutex_exit(&crashme_lock);
@@ -182,7 +182,7 @@ crashme_sysctl_forwarder(SYSCTLFN_ARGS)
int error, arg = 0;
for (cn = first_node; cn; cn = cn->cn_next) {
- if (cn->cn_sysctl == rnode)
+ if (cn->cn_sysctl == rnode->sysctl_num)
break;
}
if (!cn) {
@@ -209,20 +209,27 @@ crashme_sysctl_forwarder(SYSCTLFN_ARGS)
*/
SYSCTL_SETUP(selfdebug_crashme, "sysctl crashme setup")
{
+ const struct sysctlnode *rnode;
int rv;
size_t n;
mutex_init(&crashme_lock, MUTEX_DEFAULT, IPL_NONE);
- rv = sysctl_createv(NULL, 0, NULL, &crashme_root,
+ KASSERT(crashme_root == -1);
+
+ rv = sysctl_createv(NULL, 0, NULL, &rnode,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "crashme",
SYSCTL_DESCR("Crashme options"),
NULL, 0, NULL, 0,
CTL_DEBUG, CTL_CREATE, CTL_EOL);
- if (rv != 0 || crashme_root == NULL)
+ if (rv != 0) {
+ printf("%s: failed to create sysctl debug.crashme: %d\n",
+ __func__, rv);
return;
+ }
+ crashme_root = rnode->sysctl_num;
rv = sysctl_createv(NULL, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
@@ -230,15 +237,14 @@ SYSCTL_SETUP(selfdebug_crashme, "sysctl
SYSCTL_DESCR("Enable crashme"),
NULL, 0, &crashme_enable, 0,
CTL_DEBUG, CTL_CREATE, CTL_EOL);
+ if (rv != 0)
+ printf("%s: failed to create sysctl debug.crashme_enable:"
+ " %d\n", __func__, rv);
for (n = 0; n < __arraycount(nodes); n++) {
- crashme_node *cn = &nodes[n];
-
- rv = crashme_add(cn);
-
- /* don't insert */
- if (rv != 0)
- continue;
+ if (crashme_add(&nodes[n]))
+ printf("%s: failed to create sysctl"
+ " debug.crashme.%s\n", __func__, nodes[n].cn_name);
}
}
Index: src/sys/sys/crashme.h
diff -u src/sys/sys/crashme.h:1.1 src/sys/sys/crashme.h:1.2
--- src/sys/sys/crashme.h:1.1 Wed Jan 9 04:01:20 2019
+++ src/sys/sys/crashme.h Wed Sep 21 10:50:11 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: crashme.h,v 1.1 2019/01/09 04:01:20 mrg Exp $ */
+/* $NetBSD: crashme.h,v 1.2 2022/09/21 10:50:11 riastradh Exp $ */
/*
* Copyright (c) 2018, 2019 Matthew R. Green
@@ -47,7 +47,7 @@ typedef struct crashme_node {
const char *cn_name;
const char *cn_longname;
crashme_fn cn_fn;
- const struct sysctlnode *cn_sysctl;
+ int cn_sysctl;
struct crashme_node *cn_next;
} crashme_node;
