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opensolaris/uts/common/dtrace/fasttrap.c

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Fix several problems that can cause panics on kldload and kldunload.

	* kproc_create(fasttrap_pid_cleanup_cb, ...) gets called before
	  fasttrap_provs.fth_table gets allocated.  This can lead to a panic
	  on module load, because fasttrap_pid_cleanup_cb references
	  fasttrap_provs.fth_table.  Move kproc_create down after the point
	  that fasttrap_provs.fth_table gets allocated, and modify the error
	  handling accordingly.

	* dtrace_fasttrap_{fork,exec,exit} weren't getting NULLed until
	  after fasttrap_provs.fth_table got freed.  That caused panics on
	  module unload because fasttrap_exec_exit calls
	  fasttrap_provider_retire, which references
	  fasttrap_provs.fth_table.  NULL those function pointers earlier.

	* There wasn't any code to destroy the
	  fasttrap_{tpoints,provs,procs}.fth_table mutexes on module unload,
	  leading to a resource leak when WITNESS is enabled.  Destroy those
	  mutexes during fasttrap_unload().

Reviewed by:	markj
Approved by:	ken (mentor)
Sponsored by:	Spectra Logic
MFC after:	4 weeks
This commit is contained in:
asomers 2013-11-18 16:51:56 +00:00
parent f240b29444
commit 5b09abdb34
1 changed files with 40 additions and 23 deletions
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63
sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
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@ -2271,13 +2271,6 @@ fasttrap_load(void)
mutex_init(&fasttrap_count_mtx, "fasttrap count mtx", MUTEX_DEFAULT,
NULL);
ret = kproc_create(fasttrap_pid_cleanup_cb, NULL,
&fasttrap_cleanup_proc, 0, 0, "ftcleanup");
if (ret != 0) {
destroy_dev(fasttrap_cdev);
return (ret);
}
#if defined(sun)
fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
"fasttrap-max-probes", FASTTRAP_MAX_DEFAULT);
@ -2331,6 +2324,24 @@ fasttrap_load(void)
"providers bucket mtx", MUTEX_DEFAULT, NULL);
#endif
ret = kproc_create(fasttrap_pid_cleanup_cb, NULL,
&fasttrap_cleanup_proc, 0, 0, "ftcleanup");
if (ret != 0) {
destroy_dev(fasttrap_cdev);
#if !defined(sun)
for (i = 0; i < fasttrap_provs.fth_nent; i++)
mutex_destroy(&fasttrap_provs.fth_table[i].ftb_mtx);
for (i = 0; i < fasttrap_tpoints.fth_nent; i++)
mutex_destroy(&fasttrap_tpoints.fth_table[i].ftb_mtx);
#endif
kmem_free(fasttrap_provs.fth_table, fasttrap_provs.fth_nent *
sizeof (fasttrap_bucket_t));
mtx_destroy(&fasttrap_cleanup_mtx);
mutex_destroy(&fasttrap_count_mtx);
return (ret);
}
/*
* ... and the procs hash table.
*/
@ -2423,6 +2434,20 @@ fasttrap_unload(void)
return (-1);
}
/*
* Stop new processes from entering these hooks now, before the
* fasttrap_cleanup thread runs. That way all processes will hopefully
* be out of these hooks before we free fasttrap_provs.fth_table
*/
ASSERT(dtrace_fasttrap_fork == &fasttrap_fork);
dtrace_fasttrap_fork = NULL;
ASSERT(dtrace_fasttrap_exec == &fasttrap_exec_exit);
dtrace_fasttrap_exec = NULL;
ASSERT(dtrace_fasttrap_exit == &fasttrap_exec_exit);
dtrace_fasttrap_exit = NULL;
mtx_lock(&fasttrap_cleanup_mtx);
fasttrap_cleanup_drain = 1;
/* Wait for the cleanup thread to finish up and signal us. */
@ -2438,6 +2463,14 @@ fasttrap_unload(void)
mutex_exit(&fasttrap_count_mtx);
#endif
#if !defined(sun)
for (i = 0; i < fasttrap_tpoints.fth_nent; i++)
mutex_destroy(&fasttrap_tpoints.fth_table[i].ftb_mtx);
for (i = 0; i < fasttrap_provs.fth_nent; i++)
mutex_destroy(&fasttrap_provs.fth_table[i].ftb_mtx);
for (i = 0; i < fasttrap_procs.fth_nent; i++)
mutex_destroy(&fasttrap_procs.fth_table[i].ftb_mtx);
#endif
kmem_free(fasttrap_tpoints.fth_table,
fasttrap_tpoints.fth_nent * sizeof (fasttrap_bucket_t));
fasttrap_tpoints.fth_nent = 0;
@ -2450,22 +2483,6 @@ fasttrap_unload(void)
fasttrap_procs.fth_nent * sizeof (fasttrap_bucket_t));
fasttrap_procs.fth_nent = 0;
/*
* We know there are no tracepoints in any process anywhere in
* the system so there is no process which has its p_dtrace_count
* greater than zero, therefore we know that no thread can actively
* be executing code in fasttrap_fork(). Similarly for p_dtrace_probes
* and fasttrap_exec() and fasttrap_exit().
*/
ASSERT(dtrace_fasttrap_fork == &fasttrap_fork);
dtrace_fasttrap_fork = NULL;
ASSERT(dtrace_fasttrap_exec == &fasttrap_exec_exit);
dtrace_fasttrap_exec = NULL;
ASSERT(dtrace_fasttrap_exit == &fasttrap_exec_exit);
dtrace_fasttrap_exit = NULL;
#if !defined(sun)
destroy_dev(fasttrap_cdev);
mutex_destroy(&fasttrap_count_mtx);