Upon module load, we must take the markers mutex. It implies that the marker mutex must be nested inside the module mutex. It implies changing the nesting order : now the marker mutex nests inside the module mutex. Make the necessary changes to reverse the order in which the mutexes are taken. Includes some cleanup from Dave Hansen . Signed-off-by: Mathieu Desnoyers --- kernel/marker.c | 41 +++++++++++++++++------------------------ 1 file changed, 17 insertions(+), 24 deletions(-) Index: linux-2.6-lttng/kernel/marker.c =================================================================== --- linux-2.6-lttng.orig/kernel/marker.c 2007-11-13 10:27:22.000000000 -0500 +++ linux-2.6-lttng/kernel/marker.c 2007-11-13 13:34:19.000000000 -0500 @@ -28,7 +28,7 @@ extern struct marker __start___markers[] extern struct marker __stop___markers[]; /* - * module_mutex nests inside markers_mutex. Markers mutex protects the builtin + * markers_mutex nests inside module_mutex. Markers mutex protects the builtin * and module markers, the hash table and deferred_sync. */ static DEFINE_MUTEX(markers_mutex); @@ -257,7 +257,6 @@ static void disable_marker(struct marker * @refcount: number of references left to the given probe_module (out) * * Updates the probe callback corresponding to a range of markers. - * Must be called with markers_mutex held. */ void marker_update_probe_range(struct marker *begin, struct marker *end, struct module *probe_module, @@ -266,6 +265,7 @@ void marker_update_probe_range(struct ma struct marker *iter; struct marker_entry *mark_entry; + mutex_lock(&markers_mutex); for (iter = begin; iter < end; iter++) { mark_entry = get_marker(iter->name); if (mark_entry && mark_entry->refcount) { @@ -281,6 +281,7 @@ void marker_update_probe_range(struct ma disable_marker(iter); } } + mutex_unlock(&markers_mutex); } /* @@ -293,7 +294,6 @@ static void marker_update_probes(struct { int refcount = 0; - mutex_lock(&markers_mutex); /* Core kernel markers */ marker_update_probe_range(__start___markers, __stop___markers, probe_module, &refcount); @@ -303,7 +303,6 @@ static void marker_update_probes(struct synchronize_sched(); deferred_sync = 0; } - mutex_unlock(&markers_mutex); } /** @@ -320,7 +319,7 @@ int marker_probe_register(const char *na marker_probe_func *probe, void *private) { struct marker_entry *entry; - int ret = 0, need_update = 0; + int ret = 0; mutex_lock(&markers_mutex); entry = get_marker(name); @@ -335,11 +334,11 @@ int marker_probe_register(const char *na ret = add_marker(name, format, probe, private); if (ret) goto end; - need_update = 1; + mutex_unlock(&markers_mutex); + marker_update_probes(NULL); + return ret; end: mutex_unlock(&markers_mutex); - if (need_update) - marker_update_probes(NULL); return ret; } EXPORT_SYMBOL_GPL(marker_probe_register); @@ -355,7 +354,6 @@ void *marker_probe_unregister(const char struct module *probe_module; struct marker_entry *entry; void *private; - int need_update = 0; mutex_lock(&markers_mutex); entry = get_marker(name); @@ -368,11 +366,11 @@ void *marker_probe_unregister(const char probe_module = __module_text_address((unsigned long)entry->probe); private = remove_marker(name); deferred_sync = 1; - need_update = 1; + mutex_unlock(&markers_mutex); + marker_update_probes(probe_module); + return private; end: mutex_unlock(&markers_mutex); - if (need_update) - marker_update_probes(probe_module); return private; } EXPORT_SYMBOL_GPL(marker_probe_unregister); @@ -392,7 +390,6 @@ void *marker_probe_unregister_private_da struct marker_entry *entry; int found = 0; unsigned int i; - int need_update = 0; mutex_lock(&markers_mutex); for (i = 0; i < MARKER_TABLE_SIZE; i++) { @@ -414,11 +411,11 @@ iter_end: probe_module = __module_text_address((unsigned long)entry->probe); private = remove_marker(entry->name); deferred_sync = 1; - need_update = 1; + mutex_unlock(&markers_mutex); + marker_update_probes(probe_module); + return private; end: mutex_unlock(&markers_mutex); - if (need_update) - marker_update_probes(probe_module); return private; } EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data); @@ -434,7 +431,7 @@ EXPORT_SYMBOL_GPL(marker_probe_unregiste int marker_arm(const char *name) { struct marker_entry *entry; - int ret = 0, need_update = 0; + int ret = 0; mutex_lock(&markers_mutex); entry = get_marker(name); @@ -447,11 +444,9 @@ int marker_arm(const char *name) */ if (entry->refcount++) goto end; - need_update = 1; end: mutex_unlock(&markers_mutex); - if (need_update) - marker_update_probes(NULL); + marker_update_probes(NULL); return ret; } EXPORT_SYMBOL_GPL(marker_arm); @@ -467,7 +462,7 @@ EXPORT_SYMBOL_GPL(marker_arm); int marker_disarm(const char *name) { struct marker_entry *entry; - int ret = 0, need_update = 0; + int ret = 0; mutex_lock(&markers_mutex); entry = get_marker(name); @@ -486,11 +481,9 @@ int marker_disarm(const char *name) ret = -EPERM; goto end; } - need_update = 1; end: mutex_unlock(&markers_mutex); - if (need_update) - marker_update_probes(NULL); + marker_update_probes(NULL); return ret; } EXPORT_SYMBOL_GPL(marker_disarm); -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/