freebsd-dev/sys/cddl/dev/dtrace/dtrace_unload.c
Mark Johnston cb7320ce7b Initialize and free the DTrace taskqueue in the dtrace module load/unload
handlers rather than in the dtrace device open/close methods. The current
approach can cause a panic if the device is closed which the taskqueue
thread is active, or if a kernel module containing a provider is unloaded
while retained enablings are present and the dtrace device isn't opened.

Submitted by:	gibbs (original version)
Reviewed by:	gibbs
Approved by:	re (glebius)
MFC after:	2 weeks
2013-10-08 12:56:46 +00:00

147 lines
3.4 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* $FreeBSD$
*
*/
static int
dtrace_unload()
{
dtrace_state_t *state;
int error = 0;
#if __FreeBSD_version < 800039
/*
* Check if there is still an event handler callback
* registered.
*/
if (eh_tag != 0) {
/* De-register the device cloning event handler. */
EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
eh_tag = 0;
/* Stop device cloning. */
clone_cleanup(&dtrace_clones);
}
#else
destroy_dev(dtrace_dev);
destroy_dev(helper_dev);
#endif
mutex_enter(&dtrace_provider_lock);
mutex_enter(&dtrace_lock);
mutex_enter(&cpu_lock);
ASSERT(dtrace_opens == 0);
if (dtrace_helpers > 0) {
mutex_exit(&cpu_lock);
mutex_exit(&dtrace_lock);
mutex_exit(&dtrace_provider_lock);
return (EBUSY);
}
if (dtrace_unregister((dtrace_provider_id_t)dtrace_provider) != 0) {
mutex_exit(&cpu_lock);
mutex_exit(&dtrace_lock);
mutex_exit(&dtrace_provider_lock);
return (EBUSY);
}
dtrace_provider = NULL;
EVENTHANDLER_DEREGISTER(kld_load, dtrace_kld_load_tag);
EVENTHANDLER_DEREGISTER(kld_unload_try, dtrace_kld_unload_try_tag);
if ((state = dtrace_anon_grab()) != NULL) {
/*
* If there were ECBs on this state, the provider should
* have not been allowed to detach; assert that there is
* none.
*/
ASSERT(state->dts_necbs == 0);
dtrace_state_destroy(state);
}
bzero(&dtrace_anon, sizeof (dtrace_anon_t));
mutex_exit(&cpu_lock);
if (dtrace_helptrace_enabled) {
kmem_free(dtrace_helptrace_buffer, 0);
dtrace_helptrace_buffer = NULL;
}
if (dtrace_probes != NULL) {
kmem_free(dtrace_probes, 0);
dtrace_probes = NULL;
dtrace_nprobes = 0;
}
dtrace_hash_destroy(dtrace_bymod);
dtrace_hash_destroy(dtrace_byfunc);
dtrace_hash_destroy(dtrace_byname);
dtrace_bymod = NULL;
dtrace_byfunc = NULL;
dtrace_byname = NULL;
kmem_cache_destroy(dtrace_state_cache);
delete_unrhdr(dtrace_arena);
if (dtrace_toxrange != NULL) {
kmem_free(dtrace_toxrange, 0);
dtrace_toxrange = NULL;
dtrace_toxranges = 0;
dtrace_toxranges_max = 0;
}
ASSERT(dtrace_vtime_references == 0);
ASSERT(dtrace_opens == 0);
ASSERT(dtrace_retained == NULL);
mutex_exit(&dtrace_lock);
mutex_exit(&dtrace_provider_lock);
mutex_destroy(&dtrace_meta_lock);
mutex_destroy(&dtrace_provider_lock);
mutex_destroy(&dtrace_lock);
#ifdef DEBUG
mutex_destroy(&dtrace_errlock);
#endif
taskq_destroy(dtrace_taskq);
/* Reset our hook for exceptions. */
dtrace_invop_uninit();
/*
* Reset our hook for thread switches, but ensure that vtime isn't
* active first.
*/
dtrace_vtime_active = 0;
dtrace_vtime_switch_func = NULL;
/* Unhook from the trap handler. */
dtrace_trap_func = NULL;
return (error);
}