tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs

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: Jiri Slaby <jslaby@suse.cz>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5e9cb157d31e9828f01682221ae85af745fce5dd..952cde4d4e3c2a436869f1e32355d98c964cb380 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -434,6 +434,9 @@ 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;
@@ -443,7 +446,7 @@ 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;
 
@@ -460,6 +463,7 @@ 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;
 }
@@ -477,6 +481,9 @@ 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;
@@ -484,7 +491,7 @@ 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;
 
@@ -493,6 +500,7 @@ 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;
 }