4 files changed, 29 insertions, 13 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b549b0f5b977..6c508ff33c62 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -120,22 +120,22 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 
 /*
  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
- * can use rcu_dereference_raw() is that elements removed from this list
+ * can use rcu_dereference_raw_notrace() is that elements removed from this list
  * are simply leaked, so there is no need to interact with a grace-period
- * mechanism.  The rcu_dereference_raw() calls are needed to handle
+ * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
  * concurrent insertions into the ftrace_global_list.
  *
  * Silly Alpha and silly pointer-speculation compiler optimizations!
  */
 #define do_for_each_ftrace_op(op, list)                 \
-        op = rcu_dereference_raw(list);                 \
+        op = rcu_dereference_raw_notrace(list);                 \
         do
 
 /*
  * Optimized for just a single item in the list (as that is the normal case).
  */
 #define while_for_each_ftrace_op(op)                            \
-        while (likely(op = rcu_dereference_raw((op)->next)) &&  \
+        while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&  \
                unlikely((op) != &ftrace_list_end))
 
 static inline void ftrace_ops_init(struct ftrace_ops *ops)
@@ -779,7 +779,7 @@ ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
         if (hlist_empty(hhd))
                 return NULL;
 
-        hlist_for_each_entry_rcu(rec, hhd, node) {
+        hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
                 if (rec->ip == ip)
                         return rec;
         }
@@ -1165,7 +1165,7 @@ ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
 
         hhd = &hash->buckets[key];
 
-        hlist_for_each_entry_rcu(entry, hhd, hlist) {
+        hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
                 if (entry->ip == ip)
                         return entry;
         }
@@ -1422,8 +1422,8 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
         struct ftrace_hash *notrace_hash;
         int ret;
 
-        filter_hash = rcu_dereference_raw(ops->filter_hash);
-        notrace_hash = rcu_dereference_raw(ops->notrace_hash);
+        filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
+        notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
 
         if ((ftrace_hash_empty(filter_hash) ||
              ftrace_lookup_ip(filter_hash, ip)) &&
@@ -2920,7 +2920,7 @@ static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
          * on the hash. rcu_read_lock is too dangerous here.
          */
         preempt_disable_notrace();
-        hlist_for_each_entry_rcu(entry, hhd, node) {
+        hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
                 if (entry->ip == ip)
                         entry->ops->func(ip, parent_ip, &entry->data);
         }
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index b59aea2c48c2..e444ff88f0a4 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -620,6 +620,9 @@ int ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu,
         if (cpu == RING_BUFFER_ALL_CPUS)
                 work = &buffer->irq_work;
         else {
+                if (!cpumask_test_cpu(cpu, buffer->cpumask))
+                        return -EINVAL;
+
                 cpu_buffer = buffer->buffers[cpu];
                 work = &cpu_buffer->irq_work;
         }
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ae6fa2d1cdf7..1a41023a1f88 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -843,7 +843,15 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 
         memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
         max_data->pid = tsk->pid;
-        max_data->uid = task_uid(tsk);
+        /*
+         * If tsk == current, then use current_uid(), as that does not use
+         * RCU. The irq tracer can be called out of RCU scope.
+         */
+        if (tsk == current)
+                max_data->uid = current_uid();
+        else
+                max_data->uid = task_uid(tsk);
+
         max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
         max_data->policy = tsk->policy;
         max_data->rt_priority = tsk->rt_priority;
@@ -6216,10 +6224,15 @@ __init static int tracer_alloc_buffers(void)
 
         trace_init_cmdlines();
 
-        register_tracer(&nop_trace);
-
+        /*
+         * register_tracer() might reference current_trace, so it
+         * needs to be set before we register anything. This is
+         * just a bootstrap of current_trace anyway.
+         */
         global_trace.current_trace = &nop_trace;
 
+        register_tracer(&nop_trace);
+
         /* All seems OK, enable tracing */
         tracing_disabled = 0;
 
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 55e2cf66967b..2901e3b88590 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -1159,7 +1159,7 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
         /* stop the tracing. */
         tracing_stop();
         /* check the trace buffer */
-        ret = trace_test_buffer(tr, &count);
+        ret = trace_test_buffer(&tr->trace_buffer, &count);
         trace->reset(tr);
         tracing_start();