summaryrefslogtreecommitdiffstats
path: root/kernel/trace
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c19
-rw-r--r--kernel/trace/trace_event_perf.c31
2 files changed, 49 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 04208415798..c380612273b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1283,6 +1283,8 @@ void trace_dump_stack(void)
__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
}
+static DEFINE_PER_CPU(int, user_stack_count);
+
void
ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
{
@@ -1301,6 +1303,18 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
if (unlikely(in_nmi()))
return;
+ /*
+ * prevent recursion, since the user stack tracing may
+ * trigger other kernel events.
+ */
+ preempt_disable();
+ if (__this_cpu_read(user_stack_count))
+ goto out;
+
+ __this_cpu_inc(user_stack_count);
+
+
+
event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
@@ -1318,6 +1332,11 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
save_stack_trace_user(&trace);
if (!filter_check_discard(call, entry, buffer, event))
ring_buffer_unlock_commit(buffer, event);
+
+ __this_cpu_dec(user_stack_count);
+
+ out:
+ preempt_enable();
}
#ifdef UNUSED
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 39c059ca670..19a359d5e6d 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -21,17 +21,46 @@ typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
/* Count the events in use (per event id, not per instance) */
static int total_ref_count;
+static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
+ struct perf_event *p_event)
+{
+ /* No tracing, just counting, so no obvious leak */
+ if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
+ return 0;
+
+ /* Some events are ok to be traced by non-root users... */
+ if (p_event->attach_state == PERF_ATTACH_TASK) {
+ if (tp_event->flags & TRACE_EVENT_FL_CAP_ANY)
+ return 0;
+ }
+
+ /*
+ * ...otherwise raw tracepoint data can be a severe data leak,
+ * only allow root to have these.
+ */
+ if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return 0;
+}
+
static int perf_trace_event_init(struct ftrace_event_call *tp_event,
struct perf_event *p_event)
{
struct hlist_head __percpu *list;
- int ret = -ENOMEM;
+ int ret;
int cpu;
+ ret = perf_trace_event_perm(tp_event, p_event);
+ if (ret)
+ return ret;
+
p_event->tp_event = tp_event;
if (tp_event->perf_refcount++ > 0)
return 0;
+ ret = -ENOMEM;
+
list = alloc_percpu(struct hlist_head);
if (!list)
goto fail;