tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs

Currently trace option stacktrace is not applicable for
trace_printk with constant string argument, the reason is
in __trace_puts/__trace_bputs ftrace_trace_stack is missing.

In contrast, when using trace_printk with non constant string
argument(will call into __trace_printk/__trace_bprintk), then
trace option stacktrace is workable, this inconstant result
will confuses users a lot.

Link: http://lkml.kernel.org/p/51E7A7C9.9040401@huawei.com

Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f243444a3772..a6ffc8918dda 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -466,6 +466,9 @@ int __trace_puts(unsigned long ip, const char *str, int size)
         struct print_entry *entry;
         unsigned long irq_flags;
         int alloc;
+        int pc;
+
+        pc = preempt_count();
 
         if (unlikely(tracing_selftest_running || tracing_disabled))
                 return 0;
@@ -475,7 +478,7 @@ int __trace_puts(unsigned long ip, const char *str, int size)
         local_save_flags(irq_flags);
         buffer = global_trace.trace_buffer.buffer;
         event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, 
-                                          irq_flags, preempt_count());
+                                          irq_flags, pc);
         if (!event)
                 return 0;
 
@@ -492,6 +495,7 @@ int __trace_puts(unsigned long ip, const char *str, int size)
                 entry->buf[size] = '\0';
 
         __buffer_unlock_commit(buffer, event);
+        ftrace_trace_stack(buffer, irq_flags, 4, pc);
 
         return size;
 }
@@ -509,6 +513,9 @@ int __trace_bputs(unsigned long ip, const char *str)
         struct bputs_entry *entry;
         unsigned long irq_flags;
         int size = sizeof(struct bputs_entry);
+        int pc;
+
+        pc = preempt_count();
 
         if (unlikely(tracing_selftest_running || tracing_disabled))
                 return 0;
@@ -516,7 +523,7 @@ int __trace_bputs(unsigned long ip, const char *str)
         local_save_flags(irq_flags);
         buffer = global_trace.trace_buffer.buffer;
         event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
-                                          irq_flags, preempt_count());
+                                          irq_flags, pc);
         if (!event)
                 return 0;
 
@@ -525,6 +532,7 @@ int __trace_bputs(unsigned long ip, const char *str)
         entry->str                      = str;
 
         __buffer_unlock_commit(buffer, event);
+        ftrace_trace_stack(buffer, irq_flags, 4, pc);
 
         return 1;
 }