--- kernel/trace/trace.c
+++ kernel/trace/trace.c
@@ -748,10 +748,10 @@ out:
mutex_unlock(&trace_types_lock);
}
-static void __tracing_reset(struct trace_array *tr, int cpu)
+static void __tracing_reset(struct ring_buffer *buffer, int cpu)
{
ftrace_disable_cpu();
- ring_buffer_reset_cpu(tr->buffer, cpu);
+ ring_buffer_reset_cpu(buffer, cpu);
ftrace_enable_cpu();
}
@@ -763,7 +763,7 @@ void tracing_reset(struct trace_array *t
/* Make sure all commits have finished */
synchronize_sched();
- __tracing_reset(tr, cpu);
+ __tracing_reset(buffer, cpu);
ring_buffer_record_enable(buffer);
}
@@ -781,7 +781,7 @@ void tracing_reset_online_cpus(struct tr
tr->time_start = ftrace_now(tr->cpu);
for_each_online_cpu(cpu)
- __tracing_reset(tr, cpu);
+ __tracing_reset(buffer, cpu);
ring_buffer_record_enable(buffer);
}
@@ -858,6 +858,8 @@ void tracing_start(void)
goto out;
}
+ /* Prevent the buffers from switching */
+ __raw_spin_lock(&ftrace_max_lock);
buffer = global_trace.buffer;
if (buffer)
@@ -867,6 +869,8 @@ void tracing_start(void)
if (buffer)
ring_buffer_record_enable(buffer);
+ __raw_spin_unlock(&ftrace_max_lock);
+
ftrace_start();
out:
spin_unlock_irqrestore(&tracing_start_lock, flags);
@@ -888,6 +892,9 @@ void tracing_stop(void)
if (trace_stop_count++)
goto out;
+ /* Prevent the buffers from switching */
+ __raw_spin_lock(&ftrace_max_lock);
+
buffer = global_trace.buffer;
if (buffer)
ring_buffer_record_disable(buffer);
@@ -896,6 +903,8 @@ void tracing_stop(void)
if (buffer)
ring_buffer_record_disable(buffer);
+ __raw_spin_unlock(&ftrace_max_lock);
+
out:
spin_unlock_irqrestore(&tracing_start_lock, flags);
}
@@ -1162,6 +1171,13 @@ ftrace_trace_userstack(struct ring_buffe
if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
return;
+ /*
+ * NMIs can not handle page faults, even with fix ups.
+ * The save user stack can (and often does) fault.
+ */
+ if (unlikely(in_nmi()))
+ return;
+
event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
projects / ziggy471-frankenstein-kernel.git / blobdiff