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Linux Kernel Markers: fix marker mutex not taken upon module load

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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 <haveblue@us.ibm.com>.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mathieu Desnoyers 2007-11-14 16:59:48 -08:00 committed by Linus Torvalds
parent f433dc5634
commit 314de8a9e1
1 changed files with 17 additions and 24 deletions
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41
kernel/marker.c
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@ -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 *elem)
* @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 marker *begin,
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 marker *begin,
disable_marker(iter);
}
}
mutex_unlock(&markers_mutex);
}
/*
@ -293,7 +294,6 @@ static void marker_update_probes(struct module *probe_module)
{
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 module *probe_module)
synchronize_sched();
deferred_sync = 0;
}
mutex_unlock(&markers_mutex);
}
/**
@ -320,7 +319,7 @@ int marker_probe_register(const char *name, const char *format,
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 *name, const char *format,
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 *name)
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 *name)
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_data(void *private)
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_unregister_private_data);
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);