[PATCH 3.10 07/56] tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs

Greg Kroah-Hartman
2014-07-26T20:09:10Z

From: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>

commit 8abfb8727f4a724d31f9ccfd8013fbd16d539445 upstream.

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

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/trace.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -423,6 +423,9 @@ int __trace_puts(unsigned long ip, const
struct print_entry *entry;
unsigned long irq_flags;
int alloc;
+ int pc;
+
+ pc = preempt_count();

if (unlikely(tracing_selftest_running || tracing_disabled))
return 0;
@@ -432,7 +435,7 @@ int __trace_puts(unsigned long ip, const
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;

@@ -449,6 +452,7 @@ int __trace_puts(unsigned long ip, const
entry->buf[size] = '\0';

__buffer_unlock_commit(buffer, event);
+ ftrace_trace_stack(buffer, irq_flags, 4, pc);

return size;
}
@@ -466,6 +470,9 @@ int __trace_bputs(unsigned long ip, cons
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;
@@ -473,7 +480,7 @@ int __trace_bputs(unsigned long ip, cons
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;

@@ -482,6 +489,7 @@ int __trace_bputs(unsigned long ip, cons
entry->str = str;

__buffer_unlock_commit(buffer, event);
+ ftrace_trace_stack(buffer, irq_flags, 4, pc);

return 1;
}