On Wed, 2 Dec 2015 09:58:26 +0100
Jiri Olsa <jo...@redhat.com> wrote:
> On Tue, Dec 01, 2015 at 11:56:55AM -0500, Steven Rostedt wrote:
>
> SNIP
>
> > -static void ftrace_ops_recurs_func(unsigned long ip, unsigned long
> > parent_ip,
> > +static void ftrace_ops_assist_func(unsigned long ip, unsigned long
> > parent_ip,
> > struct ftrace_ops *op, struct pt_regs *regs)
> > {
> > int bit;
> >
> > + if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
> > + return;
> > +
> > bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
> > if (bit < 0)
> > return;
> >
> > - op->func(ip, parent_ip, op, regs);
> > + preempt_disable_notrace();
> >
> > + if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
> > + ftrace_function_local_disabled(op)) {
>
> should be !ftrace_function_local_disabled(op) in here,
> I passed my test with attached patch
>
Can you retest with this patch:
-- Steve
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index bc7f4eb6b4b0..e290a30f2d0b 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -115,9 +115,6 @@ static struct ftrace_ops *ftrace_ops_list __read_mostly =
&ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
-static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
- struct ftrace_ops *op, struct pt_regs *regs);
-
#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs);
@@ -5231,20 +5228,29 @@ static void ftrace_ops_no_ops(unsigned long ip,
unsigned long parent_ip)
/*
* If there's only one function registered but it does not support
- * recursion, this function will be called by the mcount trampoline.
- * This function will handle recursion protection.
+ * recursion, needs RCU protection and/or requires per cpu handling, then
+ * this function will be called by the mcount trampoline.
*/
-static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
+static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
int bit;
+ if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
+ return;
+
bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
if (bit < 0)
return;
- op->func(ip, parent_ip, op, regs);
+ preempt_disable_notrace();
+ if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
+ !ftrace_function_local_disabled(op)) {
+ op->func(ip, parent_ip, op, regs);
+ }
+
+ preempt_enable_notrace();
trace_clear_recursion(bit);
}
@@ -5262,12 +5268,12 @@ static void ftrace_ops_recurs_func(unsigned long ip,
unsigned long parent_ip,
ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
{
/*
- * If the func handles its own recursion, call it directly.
- * Otherwise call the recursion protected function that
- * will call the ftrace ops function.
+ * If the function does not handle recursion, needs to be RCU safe,
+ * or does per cpu logic, then we need to call the assist handler.
*/
- if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE))
- return ftrace_ops_recurs_func;
+ if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
+ ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
+ return ftrace_ops_assist_func;
return ops->func;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
