3.5.7.12 -stable review patch.  If anyone has any objections, please let me 
know.

------------------

From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org>

commit 87889501d0adfae10e3b0f0e6f2d7536eed9ae84 upstream.

Use the stack of stack_trace_call() instead of check_stack() as
the test pointer for max stack size. It makes it a bit cleaner
and a little more accurate.

Adding stable, as a later fix depends on this patch.

Signed-off-by: Steven Rostedt <rost...@goodmis.org>
[ luis: adjust context ]
Signed-off-by: Luis Henriques <luis.henriq...@canonical.com>
---
 kernel/trace/trace_stack.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index aa4270a..6ee97e5 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -40,20 +40,21 @@ static DEFINE_MUTEX(stack_sysctl_mutex);
 int stack_tracer_enabled;
 static int last_stack_tracer_enabled;
 
-static inline void check_stack(void)
+static inline void
+check_stack(unsigned long *stack)
 {
        unsigned long this_size, flags;
        unsigned long *p, *top, *start;
        int i;
 
-       this_size = ((unsigned long)&this_size) & (THREAD_SIZE-1);
+       this_size = ((unsigned long)stack) & (THREAD_SIZE-1);
        this_size = THREAD_SIZE - this_size;
 
        if (this_size <= max_stack_size)
                return;
 
        /* we do not handle interrupt stacks yet */
-       if (!object_is_on_stack(&this_size))
+       if (!object_is_on_stack(stack))
                return;
 
        local_irq_save(flags);
@@ -74,7 +75,7 @@ static inline void check_stack(void)
         * Now find where in the stack these are.
         */
        i = 0;
-       start = &this_size;
+       start = stack;
        top = (unsigned long *)
                (((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE);
 
@@ -113,6 +114,7 @@ static inline void check_stack(void)
 static void
 stack_trace_call(unsigned long ip, unsigned long parent_ip)
 {
+       unsigned long stack;
        int cpu;
 
        if (unlikely(!ftrace_enabled || stack_trace_disabled))
@@ -125,7 +127,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
        if (per_cpu(trace_active, cpu)++ != 0)
                goto out;
 
-       check_stack();
+       check_stack(&stack);
 
  out:
        per_cpu(trace_active, cpu)--;
-- 
1.8.1.2

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