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authorTom Zanussi <tzanussi@gmail.com>2009-04-17 00:27:08 -0500
committerIngo Molnar <mingo@elte.hu>2009-04-17 18:28:27 +0200
commitac1adc55fc71c7515caa2eb0e63e49b3d1c6a47c (patch)
tree7a97cf9512572c53d0802725f8e0ad6a2d4b2204 /kernel
parent46de405f25f1d9fa73b657ffbb752aa0cc87a91d (diff)
tracing/filters: add filter_mutex to protect filter predicates
This patch adds a filter_mutex to prevent the filter predicates from being accessed concurrently by various external functions. It's based on a previous patch by Li Zefan: "[PATCH 7/7] tracing/filters: make filter preds RCU safe" v2 changes: - fixed wrong value returned in a add_subsystem_pred() failure case noticed by Li Zefan. [ Impact: fix trace filter corruption/crashes on parallel access ] Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Tested-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: paulmck@linux.vnet.ibm.com LKML-Reference: <1239946028.6639.13.camel@tropicana> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.h4
-rw-r--r--kernel/trace/trace_events.c4
-rw-r--r--kernel/trace/trace_events_filter.c90
3 files changed, 75 insertions, 23 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8817c18ef97..247948e81b0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -757,13 +757,15 @@ struct filter_pred {
};
extern void filter_free_pred(struct filter_pred *pred);
-extern void filter_print_preds(struct filter_pred **preds, int n_preds,
+extern void filter_print_preds(struct ftrace_event_call *call,
struct trace_seq *s);
extern int filter_parse(char **pbuf, struct filter_pred *pred);
extern int filter_add_pred(struct ftrace_event_call *call,
struct filter_pred *pred);
extern void filter_disable_preds(struct ftrace_event_call *call);
extern void filter_free_subsystem_preds(struct event_subsystem *system);
+extern void filter_print_subsystem_preds(struct event_subsystem *system,
+ struct trace_seq *s);
extern int filter_add_subsystem_pred(struct event_subsystem *system,
struct filter_pred *pred);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1137f951be4..64f9d6d2735 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -488,7 +488,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
trace_seq_init(s);
- filter_print_preds(call->preds, call->n_preds, s);
+ filter_print_preds(call, s);
r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
kfree(s);
@@ -558,7 +558,7 @@ subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
trace_seq_init(s);
- filter_print_preds(system->preds, system->n_preds, s);
+ filter_print_subsystem_preds(system, s);
r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
kfree(s);
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index f8e5eab0424..e0fcfd2a16d 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -22,10 +22,13 @@
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ctype.h>
+#include <linux/mutex.h>
#include "trace.h"
#include "trace_output.h"
+static DEFINE_MUTEX(filter_mutex);
+
static int filter_pred_64(struct filter_pred *pred, void *event)
{
u64 *addr = (u64 *)(event + pred->offset);
@@ -112,8 +115,8 @@ int filter_match_preds(struct ftrace_event_call *call, void *rec)
}
EXPORT_SYMBOL_GPL(filter_match_preds);
-void filter_print_preds(struct filter_pred **preds, int n_preds,
- struct trace_seq *s)
+static void __filter_print_preds(struct filter_pred **preds, int n_preds,
+ struct trace_seq *s)
{
char *field_name;
struct filter_pred *pred;
@@ -138,6 +141,21 @@ void filter_print_preds(struct filter_pred **preds, int n_preds,
}
}
+void filter_print_preds(struct ftrace_event_call *call, struct trace_seq *s)
+{
+ mutex_lock(&filter_mutex);
+ __filter_print_preds(call->preds, call->n_preds, s);
+ mutex_unlock(&filter_mutex);
+}
+
+void filter_print_subsystem_preds(struct event_subsystem *system,
+ struct trace_seq *s)
+{
+ mutex_lock(&filter_mutex);
+ __filter_print_preds(system->preds, system->n_preds, s);
+ mutex_unlock(&filter_mutex);
+}
+
static struct ftrace_event_field *
find_event_field(struct ftrace_event_call *call, char *name)
{
@@ -180,7 +198,7 @@ static int filter_set_pred(struct filter_pred *dest,
return 0;
}
-void filter_disable_preds(struct ftrace_event_call *call)
+static void __filter_disable_preds(struct ftrace_event_call *call)
{
int i;
@@ -190,6 +208,13 @@ void filter_disable_preds(struct ftrace_event_call *call)
call->preds[i]->fn = filter_pred_none;
}
+void filter_disable_preds(struct ftrace_event_call *call)
+{
+ mutex_lock(&filter_mutex);
+ __filter_disable_preds(call);
+ mutex_unlock(&filter_mutex);
+}
+
int init_preds(struct ftrace_event_call *call)
{
struct filter_pred *pred;
@@ -223,7 +248,7 @@ oom:
}
EXPORT_SYMBOL_GPL(init_preds);
-void filter_free_subsystem_preds(struct event_subsystem *system)
+static void __filter_free_subsystem_preds(struct event_subsystem *system)
{
struct ftrace_event_call *call;
int i;
@@ -241,18 +266,25 @@ void filter_free_subsystem_preds(struct event_subsystem *system)
continue;
if (!strcmp(call->system, system->name))
- filter_disable_preds(call);
+ __filter_disable_preds(call);
}
}
-static int __filter_add_pred(struct ftrace_event_call *call,
- struct filter_pred *pred,
- filter_pred_fn_t fn)
+void filter_free_subsystem_preds(struct event_subsystem *system)
+{
+ mutex_lock(&filter_mutex);
+ __filter_free_subsystem_preds(system);
+ mutex_unlock(&filter_mutex);
+}
+
+static int filter_add_pred_fn(struct ftrace_event_call *call,
+ struct filter_pred *pred,
+ filter_pred_fn_t fn)
{
int idx, err;
if (call->n_preds && !pred->compound)
- filter_disable_preds(call);
+ __filter_disable_preds(call);
if (call->n_preds == MAX_FILTER_PRED)
return -ENOSPC;
@@ -276,7 +308,8 @@ static int is_string_field(const char *type)
return 0;
}
-int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
+static int __filter_add_pred(struct ftrace_event_call *call,
+ struct filter_pred *pred)
{
struct ftrace_event_field *field;
filter_pred_fn_t fn;
@@ -293,7 +326,7 @@ int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
return -EINVAL;
fn = filter_pred_string;
pred->str_len = field->size;
- return __filter_add_pred(call, pred, fn);
+ return filter_add_pred_fn(call, pred, fn);
} else {
if (pred->str_len)
return -EINVAL;
@@ -316,7 +349,18 @@ int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
return -EINVAL;
}
- return __filter_add_pred(call, pred, fn);
+ return filter_add_pred_fn(call, pred, fn);
+}
+
+int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
+{
+ int err;
+
+ mutex_lock(&filter_mutex);
+ err = __filter_add_pred(call, pred);
+ mutex_unlock(&filter_mutex);
+
+ return err;
}
int filter_add_subsystem_pred(struct event_subsystem *system,
@@ -324,20 +368,27 @@ int filter_add_subsystem_pred(struct event_subsystem *system,
{
struct ftrace_event_call *call;
+ mutex_lock(&filter_mutex);
+
if (system->n_preds && !pred->compound)
- filter_free_subsystem_preds(system);
+ __filter_free_subsystem_preds(system);
if (!system->n_preds) {
system->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
GFP_KERNEL);
- if (!system->preds)
+ if (!system->preds) {
+ mutex_unlock(&filter_mutex);
return -ENOMEM;
+ }
}
- if (system->n_preds == MAX_FILTER_PRED)
+ if (system->n_preds == MAX_FILTER_PRED) {
+ mutex_unlock(&filter_mutex);
return -ENOSPC;
+ }
system->preds[system->n_preds] = pred;
+ system->n_preds++;
list_for_each_entry(call, &ftrace_events, list) {
int err;
@@ -348,17 +399,16 @@ int filter_add_subsystem_pred(struct event_subsystem *system,
if (strcmp(call->system, system->name))
continue;
- if (!find_event_field(call, pred->field_name))
- continue;
-
- err = filter_add_pred(call, pred);
+ err = __filter_add_pred(call, pred);
if (err == -ENOMEM) {
system->preds[system->n_preds] = NULL;
+ system->n_preds--;
+ mutex_unlock(&filter_mutex);
return err;
}
}
- system->n_preds++;
+ mutex_unlock(&filter_mutex);
return 0;
}