Commit 7a80876d authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Kamal Mostafa

ftrace: Fix breakage of set_ftrace_pid

commit e3eea140 upstream.

Commit 4104d326 ("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.
Reported-by: default avatarMatt Fleming <matt@console-pimps.org>
Reported-by: default avatarRichard Weinberger <richard.weinberger@gmail.com>
Tested-by: default avatarMatt Fleming <matt@console-pimps.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
parent 2ecf7c4f
...@@ -116,6 +116,7 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); ...@@ -116,6 +116,7 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
* SAVE_REGS. If another ops with this flag set is already registered * SAVE_REGS. If another ops with this flag set is already registered
* for any of the functions that this ops will be registered for, then * for any of the functions that this ops will be registered for, then
* this ops will fail to register or set_filter_ip. * this ops will fail to register or set_filter_ip.
* PID - Is affected by set_ftrace_pid (allows filtering on those pids)
*/ */
enum { enum {
FTRACE_OPS_FL_ENABLED = 1 << 0, FTRACE_OPS_FL_ENABLED = 1 << 0,
...@@ -132,6 +133,7 @@ enum { ...@@ -132,6 +133,7 @@ enum {
FTRACE_OPS_FL_MODIFYING = 1 << 11, FTRACE_OPS_FL_MODIFYING = 1 << 11,
FTRACE_OPS_FL_ALLOC_TRAMP = 1 << 12, FTRACE_OPS_FL_ALLOC_TRAMP = 1 << 12,
FTRACE_OPS_FL_IPMODIFY = 1 << 13, FTRACE_OPS_FL_IPMODIFY = 1 << 13,
FTRACE_OPS_FL_PID = 1 << 14,
}; };
#ifdef CONFIG_DYNAMIC_FTRACE #ifdef CONFIG_DYNAMIC_FTRACE
...@@ -159,6 +161,7 @@ struct ftrace_ops { ...@@ -159,6 +161,7 @@ struct ftrace_ops {
struct ftrace_ops *next; struct ftrace_ops *next;
unsigned long flags; unsigned long flags;
void *private; void *private;
ftrace_func_t saved_func;
int __percpu *disabled; int __percpu *disabled;
#ifdef CONFIG_DYNAMIC_FTRACE #ifdef CONFIG_DYNAMIC_FTRACE
int nr_trampolines; int nr_trampolines;
......
...@@ -98,6 +98,13 @@ struct ftrace_pid { ...@@ -98,6 +98,13 @@ struct ftrace_pid {
struct pid *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 set when an anomaly is discovered.
* ftrace_disabled is much stronger than ftrace_enabled. * ftrace_disabled is much stronger than ftrace_enabled.
...@@ -109,7 +116,6 @@ static DEFINE_MUTEX(ftrace_lock); ...@@ -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_control_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_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_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 global_ops;
static struct ftrace_ops control_ops; static struct ftrace_ops control_ops;
...@@ -183,14 +189,7 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, ...@@ -183,14 +189,7 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
if (!test_tsk_trace_trace(current)) if (!test_tsk_trace_trace(current))
return; return;
ftrace_pid_function(ip, parent_ip, op, regs); op->saved_func(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;
} }
/** /**
...@@ -202,7 +201,6 @@ static void set_ftrace_pid_function(ftrace_func_t func) ...@@ -202,7 +201,6 @@ static void set_ftrace_pid_function(ftrace_func_t func)
void clear_ftrace_function(void) void clear_ftrace_function(void)
{ {
ftrace_trace_function = ftrace_stub; ftrace_trace_function = ftrace_stub;
ftrace_pid_function = ftrace_stub;
} }
static void control_ops_disable_all(struct ftrace_ops *ops) static void control_ops_disable_all(struct ftrace_ops *ops)
...@@ -423,6 +421,12 @@ static int __register_ftrace_function(struct ftrace_ops *ops) ...@@ -423,6 +421,12 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
} else } else
add_ftrace_ops(&ftrace_ops_list, ops); 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); ftrace_update_trampoline(ops);
if (ftrace_enabled) if (ftrace_enabled)
...@@ -450,15 +454,28 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) ...@@ -450,15 +454,28 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (ftrace_enabled) if (ftrace_enabled)
update_ftrace_function(); update_ftrace_function();
ops->func = ops->saved_func;
return 0; return 0;
} }
static void ftrace_update_pid_func(void) static void ftrace_update_pid_func(void)
{ {
bool enabled = ftrace_pids_enabled();
struct ftrace_ops *op;
/* Only do something if we are tracing something */ /* Only do something if we are tracing something */
if (ftrace_trace_function == ftrace_stub) if (ftrace_trace_function == ftrace_stub)
return; 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(); update_ftrace_function();
} }
...@@ -1120,7 +1137,8 @@ static struct ftrace_ops global_ops = { ...@@ -1120,7 +1137,8 @@ static struct ftrace_ops global_ops = {
.local_hash.filter_hash = EMPTY_HASH, .local_hash.filter_hash = EMPTY_HASH,
INIT_OPS_HASH(global_ops) INIT_OPS_HASH(global_ops)
.flags = FTRACE_OPS_FL_RECURSION_SAFE | .flags = FTRACE_OPS_FL_RECURSION_SAFE |
FTRACE_OPS_FL_INITIALIZED, FTRACE_OPS_FL_INITIALIZED |
FTRACE_OPS_FL_PID,
}; };
/* /*
...@@ -5010,7 +5028,9 @@ static void ftrace_update_trampoline(struct ftrace_ops *ops) ...@@ -5010,7 +5028,9 @@ static void ftrace_update_trampoline(struct ftrace_ops *ops)
static struct ftrace_ops global_ops = { static struct ftrace_ops global_ops = {
.func = ftrace_stub, .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) static int __init ftrace_nodyn_init(void)
...@@ -5067,11 +5087,6 @@ void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) ...@@ -5067,11 +5087,6 @@ void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
if (WARN_ON(tr->ops->func != ftrace_stub)) if (WARN_ON(tr->ops->func != ftrace_stub))
printk("ftrace ops had %pS for function\n", printk("ftrace ops had %pS for function\n",
tr->ops->func); 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->func = func;
tr->ops->private = tr; tr->ops->private = tr;
...@@ -5365,7 +5380,7 @@ static void *fpid_start(struct seq_file *m, loff_t *pos) ...@@ -5365,7 +5380,7 @@ static void *fpid_start(struct seq_file *m, loff_t *pos)
{ {
mutex_lock(&ftrace_lock); mutex_lock(&ftrace_lock);
if (list_empty(&ftrace_pids) && (!*pos)) if (!ftrace_pids_enabled() && (!*pos))
return (void *) 1; return (void *) 1;
return seq_list_start(&ftrace_pids, *pos); return seq_list_start(&ftrace_pids, *pos);
...@@ -5604,6 +5619,7 @@ static struct ftrace_ops graph_ops = { ...@@ -5604,6 +5619,7 @@ static struct ftrace_ops graph_ops = {
.func = ftrace_stub, .func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | .flags = FTRACE_OPS_FL_RECURSION_SAFE |
FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_INITIALIZED |
FTRACE_OPS_FL_PID |
FTRACE_OPS_FL_STUB, FTRACE_OPS_FL_STUB,
#ifdef FTRACE_GRAPH_TRAMP_ADDR #ifdef FTRACE_GRAPH_TRAMP_ADDR
.trampoline = FTRACE_GRAPH_TRAMP_ADDR, .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment