Module Name: src
Committed By: mrg
Date: Wed Jan 9 04:01:20 UTC 2019
Modified Files:
src/sys/kern: files.kern
Added Files:
src/sys/kern: kern_crashme.c
src/sys/sys: crashme.h
Log Message:
crashme: a framework to test kernel faults.
so far, only a basic panic() and null deref nodes are added.
with options DEBUG, one can now use:
# sysctl -w kern.crashme_enable=1
# sysctl -w kern.crashme.panic=1
# sysctl -w kern.crashme.null_deref=1
to trigger a crash. crashme_enable must be set to 1 before any
of the nodes will be writeable.
supports dynamic additional/removal of crashme nodes.
(obsoletes kern.panic_now, which will be removed later.)
To generate a diff of this commit:
cvs rdiff -u -r1.29 -r1.30 src/sys/kern/files.kern
cvs rdiff -u -r0 -r1.1 src/sys/kern/kern_crashme.c
cvs rdiff -u -r0 -r1.1 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/files.kern
diff -u src/sys/kern/files.kern:1.29 src/sys/kern/files.kern:1.30
--- src/sys/kern/files.kern:1.29 Mon Dec 24 16:58:54 2018
+++ src/sys/kern/files.kern Wed Jan 9 04:01:20 2019
@@ -1,4 +1,4 @@
-# $NetBSD: files.kern,v 1.29 2018/12/24 16:58:54 thorpej Exp $
+# $NetBSD: files.kern,v 1.30 2019/01/09 04:01:20 mrg Exp $
#
# kernel sources
@@ -77,6 +77,7 @@ file kern/kern_rwlock.c kern
file kern/kern_rwlock_obj.c kern
file kern/kern_scdebug.c kern
file kern/kern_sdt.c kdtrace_hooks
+file kern/kern_crashme.c debug
file kern/kern_sig.c kern
file kern/kern_sleepq.c kern
file kern/kern_softint.c kern
Added files:
Index: src/sys/kern/kern_crashme.c
diff -u /dev/null src/sys/kern/kern_crashme.c:1.1
--- /dev/null Wed Jan 9 04:01:20 2019
+++ src/sys/kern/kern_crashme.c Wed Jan 9 04:01:20 2019
@@ -0,0 +1,236 @@
+/* $NetBSD: kern_crashme.c,v 1.1 2019/01/09 04:01:20 mrg Exp $ */
+
+/*
+ * Copyright (c) 2018, 2019 Matthew R. Green
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * kern_crashme.c: special debugging routines only enabled in DEBUG
+ * enabled kernels, designed for debugging kernel crashes.
+ *
+ * supports crashme sysctl nodes, to test various ways the system can
+ * panic or crash. you can add and remove nodes.
+ */
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/systm.h>
+#include <sys/kthread.h>
+#include <sys/kmem.h>
+#include <sys/mutex.h>
+#include <sys/crashme.h>
+
+#define DPRINTF(fmt, ...) \
+ printf("%s:%d: " fmt "\n", __func__, __LINE__, ## __VA_ARGS__)
+
+static int crashme_sysctl_forwarder(SYSCTLFN_PROTO);
+
+static int crashme_panic(int);
+static int crashme_null_deref(int);
+
+#define CMNODE(name, lname, func) \
+ { \
+ .cn_name = name, \
+ .cn_longname = lname, \
+ .cn_fn = func, \
+ }
+
+static crashme_node nodes[] = {
+ CMNODE("panic", "plain old panic", crashme_panic),
+ CMNODE("null_deref", "null dereference", crashme_null_deref),
+};
+static crashme_node *first_node;
+static kmutex_t crashme_lock;
+static const struct sysctlnode *crashme_root = NULL;
+static bool crashme_enable = 0;
+
+/*
+ * add a crashme node dynamically. return -1 on failure, 0 on success.
+ */
+int
+crashme_add(crashme_node *ncn)
+{
+ int rv = -1;
+ crashme_node *cn;
+ crashme_node *last = NULL;
+
+ if (crashme_root == NULL)
+ return -1;
+
+ mutex_enter(&crashme_lock);
+ for (cn = first_node; cn; last = cn, cn = cn->cn_next) {
+ if (strcmp(cn->cn_name, ncn->cn_name) == 0)
+ break;
+ }
+ 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);
+
+ /* don't insert upon failure */
+ if (rv == 0) {
+ if (last)
+ last->cn_next = ncn;
+ if (first_node == NULL)
+ first_node = ncn;
+ }
+ }
+ mutex_exit(&crashme_lock);
+
+ return rv;
+}
+
+/*
+ * remove a crashme node. return -1 on failure, 0 on success.
+ */
+int
+crashme_remove(crashme_node *rcn)
+{
+ crashme_node *cn, *prev = NULL;
+
+ mutex_enter(&crashme_lock);
+ for (cn = first_node; cn; prev = cn, cn = cn->cn_next) {
+ int rv;
+
+ if (cn != rcn)
+ continue;
+
+ if (cn == first_node)
+ first_node = cn->cn_next;
+ if (prev)
+ prev->cn_next = cn->cn_next;
+
+ if ((rv = sysctl_destroyv(NULL, CTL_DEBUG, crashme_root,
+ cn->cn_name, CTL_EOL)) == 0)
+ printf("%s: unable to remove %s from sysctl\n",
+ __func__, cn->cn_name);
+ break;
+ }
+ mutex_exit(&crashme_lock);
+
+ if (cn == NULL)
+ return -1;
+
+ return 0;
+}
+
+/*
+ * list or execute a crashme node
+ */
+static int
+crashme_sysctl_forwarder(SYSCTLFN_ARGS)
+{
+ struct sysctlnode node;
+ crashme_node *cn;
+ int error, arg = 0;
+
+ for (cn = first_node; cn; cn = cn->cn_next) {
+ if (cn->cn_sysctl == rnode)
+ break;
+ }
+ if (!cn) {
+ return EINVAL;
+ }
+
+ node = *rnode;
+ node.sysctl_data = &arg;
+ error = sysctl_lookup(SYSCTLFN_CALL(&node));
+ if (error || newp == NULL)
+ return (error);
+
+ if (!crashme_enable)
+ return EACCES;
+
+ DPRINTF("invoking \"%s\" (%s)", cn->cn_name, cn->cn_longname);
+ if ((*cn->cn_fn)(arg) != 0)
+ panic("crashme on %s failed!\n", cn->cn_name);
+ return 0;
+}
+
+/*
+ * register the various nodes with sysctl.
+ */
+SYSCTL_SETUP(selfdebug_crashme, "sysctl crashme setup")
+{
+ int rv;
+ size_t n;
+
+ mutex_init(&crashme_lock, MUTEX_DEFAULT, IPL_NONE);
+
+ rv = sysctl_createv(NULL, 0, NULL, &crashme_root,
+ 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)
+ return;
+
+ rv = sysctl_createv(NULL, 0, NULL, NULL,
+ CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
+ CTLTYPE_BOOL, "crashme_enable",
+ SYSCTL_DESCR("Enable crashme"),
+ NULL, 0, &crashme_enable, 0,
+ CTL_DEBUG, CTL_CREATE, CTL_EOL);
+
+ for (n = 0; n < __arraycount(nodes); n++) {
+ crashme_node *cn = &nodes[n];
+
+ rv = crashme_add(cn);
+
+ /* don't insert */
+ if (rv != 0)
+ continue;
+ }
+}
+
+/*
+ * actual panic functions below
+ */
+static int
+crashme_panic(int flags)
+{
+
+ panic("crashme plain old panic");
+ return -1;
+}
+
+static int
+crashme_null_deref(int flags)
+{
+
+ *(char *)0 = 0;
+ return -1;
+}
Index: src/sys/sys/crashme.h
diff -u /dev/null src/sys/sys/crashme.h:1.1
--- /dev/null Wed Jan 9 04:01:20 2019
+++ src/sys/sys/crashme.h Wed Jan 9 04:01:20 2019
@@ -0,0 +1,57 @@
+/* $NetBSD: crashme.h,v 1.1 2019/01/09 04:01:20 mrg Exp $ */
+
+/*
+ * Copyright (c) 2018, 2019 Matthew R. Green
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* header for kernel crashme node handling. */
+
+#ifndef _SYS_CRASHME_H_
+#define _SYS_CRASHME_H_
+
+/*
+ * don't mark this __dead. crashme nodes failures should return to
+ * the caller so it can be handled.
+ *
+ * return zero if successful, and should return to user (may be part
+ * of the setup needed.) return non-zero otherwise (will call plain
+ * panic().)
+ */
+typedef int (*crashme_fn)(int);
+
+typedef struct crashme_node {
+ const char *cn_name;
+ const char *cn_longname;
+ crashme_fn cn_fn;
+ const struct sysctlnode *cn_sysctl;
+ struct crashme_node *cn_next;
+} crashme_node;
+
+int crashme_add(crashme_node *ncn);
+int crashme_remove(crashme_node *ncn);
+
+#endif /* _SYS_CRASHME_H_ */
