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authorSteven Rostedt (Red Hat)2015-07-24 10:38:12 -0400
committerSteven Rostedt2015-07-24 13:58:14 -0400
commite3eea1404f5ff7a2ceb7b5e7ba412a6fd94f2935 (patch)
tree2c2cd04a98518380122739dae0eccf86ea979760 /kernel
parentd6726c8145290bef950ae2538ea6ae1d96a1944b (diff)
ftrace: Fix breakage of set_ftrace_pid
Commit 4104d326b670 ("ftrace: Remove global function list and call function directly") simplified the ftrace code by removing the global_ops list with a new design. But this cleanup also broke the filtering of PIDs that are added to the set_ftrace_pid file. Add back the proper hooks to have pid filtering working once again. Cc: stable@vger.kernel.org # 3.16+ Reported-by: Matt Fleming <matt@console-pimps.org> Reported-by: Richard Weinberger <richard.weinberger@gmail.com> Tested-by: Matt Fleming <matt@console-pimps.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c52
1 files changed, 34 insertions, 18 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 02bece4a99ea..eb11011b5292 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -98,6 +98,13 @@ struct ftrace_pid {
struct pid *pid;
};
+static bool ftrace_pids_enabled(void)
+{
+ return !list_empty(&ftrace_pids);
+}
+
+static void ftrace_update_trampoline(struct ftrace_ops *ops);
+
/*
* ftrace_disabled is set when an anomaly is discovered.
* ftrace_disabled is much stronger than ftrace_enabled.
@@ -109,7 +116,6 @@ static DEFINE_MUTEX(ftrace_lock);
static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
-ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
static struct ftrace_ops control_ops;
@@ -183,14 +189,7 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
if (!test_tsk_trace_trace(current))
return;
- ftrace_pid_function(ip, parent_ip, op, regs);
-}
-
-static void set_ftrace_pid_function(ftrace_func_t func)
-{
- /* do not set ftrace_pid_function to itself! */
- if (func != ftrace_pid_func)
- ftrace_pid_function = func;
+ op->saved_func(ip, parent_ip, op, regs);
}
/**
@@ -202,7 +201,6 @@ static void set_ftrace_pid_function(ftrace_func_t func)
void clear_ftrace_function(void)
{
ftrace_trace_function = ftrace_stub;
- ftrace_pid_function = ftrace_stub;
}
static void control_ops_disable_all(struct ftrace_ops *ops)
@@ -436,6 +434,12 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
} else
add_ftrace_ops(&ftrace_ops_list, ops);
+ /* Always save the function, and reset at unregistering */
+ ops->saved_func = ops->func;
+
+ if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled())
+ ops->func = ftrace_pid_func;
+
ftrace_update_trampoline(ops);
if (ftrace_enabled)
@@ -463,15 +467,28 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (ftrace_enabled)
update_ftrace_function();
+ ops->func = ops->saved_func;
+
return 0;
}
static void ftrace_update_pid_func(void)
{
+ bool enabled = ftrace_pids_enabled();
+ struct ftrace_ops *op;
+
/* Only do something if we are tracing something */
if (ftrace_trace_function == ftrace_stub)
return;
+ do_for_each_ftrace_op(op, ftrace_ops_list) {
+ if (op->flags & FTRACE_OPS_FL_PID) {
+ op->func = enabled ? ftrace_pid_func :
+ op->saved_func;
+ ftrace_update_trampoline(op);
+ }
+ } while_for_each_ftrace_op(op);
+
update_ftrace_function();
}
@@ -1133,7 +1150,8 @@ static struct ftrace_ops global_ops = {
.local_hash.filter_hash = EMPTY_HASH,
INIT_OPS_HASH(global_ops)
.flags = FTRACE_OPS_FL_RECURSION_SAFE |
- FTRACE_OPS_FL_INITIALIZED,
+ FTRACE_OPS_FL_INITIALIZED |
+ FTRACE_OPS_FL_PID,
};
/*
@@ -5023,7 +5041,9 @@ static void ftrace_update_trampoline(struct ftrace_ops *ops)
static struct ftrace_ops global_ops = {
.func = ftrace_stub,
- .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+ .flags = FTRACE_OPS_FL_RECURSION_SAFE |
+ FTRACE_OPS_FL_INITIALIZED |
+ FTRACE_OPS_FL_PID,
};
static int __init ftrace_nodyn_init(void)
@@ -5080,11 +5100,6 @@ void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
if (WARN_ON(tr->ops->func != ftrace_stub))
printk("ftrace ops had %pS for function\n",
tr->ops->func);
- /* Only the top level instance does pid tracing */
- if (!list_empty(&ftrace_pids)) {
- set_ftrace_pid_function(func);
- func = ftrace_pid_func;
- }
}
tr->ops->func = func;
tr->ops->private = tr;
@@ -5371,7 +5386,7 @@ static void *fpid_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&ftrace_lock);
- if (list_empty(&ftrace_pids) && (!*pos))
+ if (!ftrace_pids_enabled() && (!*pos))
return (void *) 1;
return seq_list_start(&ftrace_pids, *pos);
@@ -5610,6 +5625,7 @@ static struct ftrace_ops graph_ops = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE |
FTRACE_OPS_FL_INITIALIZED |
+ FTRACE_OPS_FL_PID |
FTRACE_OPS_FL_STUB,
#ifdef FTRACE_GRAPH_TRAMP_ADDR
.trampoline = FTRACE_GRAPH_TRAMP_ADDR,