mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-14 06:35:12 +00:00
tracing/kprobes: Use rcu_dereference_raw for tp->files
Use rcu_dereference_raw() for accessing tp->files. Because the write-side uses rcu_assign_pointer() for memory barrier, the read-side also has to use rcu_dereference_raw() with read memory barrier. Link: http://lkml.kernel.org/r/20130513115834.6545.17022.stgit@mhiramat-M0-7522 Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tom Zanussi <tom.zanussi@intel.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
parent
60705c8946
commit
c02c7e65d9
1 changed files with 37 additions and 10 deletions
|
@ -185,9 +185,14 @@ static struct trace_probe *find_trace_probe(const char *event,
|
||||||
|
|
||||||
static int trace_probe_nr_files(struct trace_probe *tp)
|
static int trace_probe_nr_files(struct trace_probe *tp)
|
||||||
{
|
{
|
||||||
struct ftrace_event_file **file = tp->files;
|
struct ftrace_event_file **file;
|
||||||
int ret = 0;
|
int ret = 0;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Since all tp->files updater is protected by probe_enable_lock,
|
||||||
|
* we don't need to lock an rcu_read_lock.
|
||||||
|
*/
|
||||||
|
file = rcu_dereference_raw(tp->files);
|
||||||
if (file)
|
if (file)
|
||||||
while (*(file++))
|
while (*(file++))
|
||||||
ret++;
|
ret++;
|
||||||
|
@ -209,9 +214,10 @@ enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
|
||||||
mutex_lock(&probe_enable_lock);
|
mutex_lock(&probe_enable_lock);
|
||||||
|
|
||||||
if (file) {
|
if (file) {
|
||||||
struct ftrace_event_file **new, **old = tp->files;
|
struct ftrace_event_file **new, **old;
|
||||||
int n = trace_probe_nr_files(tp);
|
int n = trace_probe_nr_files(tp);
|
||||||
|
|
||||||
|
old = rcu_dereference_raw(tp->files);
|
||||||
/* 1 is for new one and 1 is for stopper */
|
/* 1 is for new one and 1 is for stopper */
|
||||||
new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
|
new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
|
||||||
GFP_KERNEL);
|
GFP_KERNEL);
|
||||||
|
@ -251,11 +257,17 @@ enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
|
||||||
static int
|
static int
|
||||||
trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file)
|
trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file)
|
||||||
{
|
{
|
||||||
|
struct ftrace_event_file **files;
|
||||||
int i;
|
int i;
|
||||||
|
|
||||||
if (tp->files) {
|
/*
|
||||||
for (i = 0; tp->files[i]; i++)
|
* Since all tp->files updater is protected by probe_enable_lock,
|
||||||
if (tp->files[i] == file)
|
* we don't need to lock an rcu_read_lock.
|
||||||
|
*/
|
||||||
|
files = rcu_dereference_raw(tp->files);
|
||||||
|
if (files) {
|
||||||
|
for (i = 0; files[i]; i++)
|
||||||
|
if (files[i] == file)
|
||||||
return i;
|
return i;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -274,10 +286,11 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
|
||||||
mutex_lock(&probe_enable_lock);
|
mutex_lock(&probe_enable_lock);
|
||||||
|
|
||||||
if (file) {
|
if (file) {
|
||||||
struct ftrace_event_file **new, **old = tp->files;
|
struct ftrace_event_file **new, **old;
|
||||||
int n = trace_probe_nr_files(tp);
|
int n = trace_probe_nr_files(tp);
|
||||||
int i, j;
|
int i, j;
|
||||||
|
|
||||||
|
old = rcu_dereference_raw(tp->files);
|
||||||
if (n == 0 || trace_probe_file_index(tp, file) < 0) {
|
if (n == 0 || trace_probe_file_index(tp, file) < 0) {
|
||||||
ret = -EINVAL;
|
ret = -EINVAL;
|
||||||
goto out_unlock;
|
goto out_unlock;
|
||||||
|
@ -872,9 +885,16 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
|
||||||
static __kprobes void
|
static __kprobes void
|
||||||
kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
|
kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
|
||||||
{
|
{
|
||||||
struct ftrace_event_file **file = tp->files;
|
/*
|
||||||
|
* Note: preempt is already disabled around the kprobe handler.
|
||||||
|
* However, we still need an smp_read_barrier_depends() corresponding
|
||||||
|
* to smp_wmb() in rcu_assign_pointer() to access the pointer.
|
||||||
|
*/
|
||||||
|
struct ftrace_event_file **file = rcu_dereference_raw(tp->files);
|
||||||
|
|
||||||
|
if (unlikely(!file))
|
||||||
|
return;
|
||||||
|
|
||||||
/* Note: preempt is already disabled around the kprobe handler */
|
|
||||||
while (*file) {
|
while (*file) {
|
||||||
__kprobe_trace_func(tp, regs, *file);
|
__kprobe_trace_func(tp, regs, *file);
|
||||||
file++;
|
file++;
|
||||||
|
@ -925,9 +945,16 @@ static __kprobes void
|
||||||
kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
|
kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
|
||||||
struct pt_regs *regs)
|
struct pt_regs *regs)
|
||||||
{
|
{
|
||||||
struct ftrace_event_file **file = tp->files;
|
/*
|
||||||
|
* Note: preempt is already disabled around the kprobe handler.
|
||||||
|
* However, we still need an smp_read_barrier_depends() corresponding
|
||||||
|
* to smp_wmb() in rcu_assign_pointer() to access the pointer.
|
||||||
|
*/
|
||||||
|
struct ftrace_event_file **file = rcu_dereference_raw(tp->files);
|
||||||
|
|
||||||
|
if (unlikely(!file))
|
||||||
|
return;
|
||||||
|
|
||||||
/* Note: preempt is already disabled around the kprobe handler */
|
|
||||||
while (*file) {
|
while (*file) {
|
||||||
__kretprobe_trace_func(tp, ri, regs, *file);
|
__kretprobe_trace_func(tp, ri, regs, *file);
|
||||||
file++;
|
file++;
|
||||||
|
|
Loading…
Reference in a new issue