[RFC PATCH 03/12 v3] ptrace: avoid using task->ptrace when possible in ptrace.{c,h}

Oleg Nesterov
2009-05-30T22:45:01Z

Do some s/->ptrace/task_ptrace()/ changes in ptrace.{c,h} as a preparation
for the future changes.

Change ptrace_setoptions() to access ->ptrace only once.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---

include/linux/ptrace.h | 31 ++++++++++++++++---------------
kernel/ptrace.c | 28 +++++++++++++++-------------
2 files changed, 31 insertions(+), 28 deletions(-)

--- PTRACE/include/linux/ptrace.h~03_PTRACE 2009-05-30 21:18:38.000000000 +0200
+++ PTRACE/include/linux/ptrace.h 2009-05-30 22:44:41.000000000 +0200
@@ -106,15 +106,27 @@ static inline int ptrace_reparented(stru
{
return child->real_parent != child->parent;
}
+
+/**
+ * task_ptrace - return %PT_* flags that apply to a task
+ * @task: pointer to &task_struct in question
+ *
+ * Returns the %PT_* flags that apply to @task.
+ */
+static inline int task_ptrace(struct task_struct *task)
+{
+ return task->ptrace;
+}
+
static inline void ptrace_link(struct task_struct *child,
struct task_struct *new_parent)
{
- if (unlikely(child->ptrace))
+ if (unlikely(task_ptrace(child)))
__ptrace_link(child, new_parent);
}
static inline void ptrace_unlink(struct task_struct *child)
{
- if (unlikely(child->ptrace))
+ if (unlikely(task_ptrace(child)))
__ptrace_unlink(child);
}

@@ -122,19 +134,8 @@ int generic_ptrace_peekdata(struct task_
int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);

/**
- * task_ptrace - return %PT_* flags that apply to a task
- * @task: pointer to &task_struct in question
- *
- * Returns the %PT_* flags that apply to @task.
- */
-static inline int task_ptrace(struct task_struct *task)
-{
- return task->ptrace;
-}
-
-/**
* ptrace_event - possibly stop for a ptrace event notification
- * @mask: %PT_* bit to check in @current->ptrace
+ * @mask: %PT_* bit to check in task_ptrace(@current)
* @event: %PTRACE_EVENT_* value to report if @mask is set
* @message: value for %PTRACE_GETEVENTMSG to return
*
@@ -147,7 +148,7 @@ static inline int task_ptrace(struct tas
*/
static inline int ptrace_event(int mask, int event, unsigned long message)
{
- if (mask && likely(!(current->ptrace & mask)))
+ if (mask && likely(!(task_ptrace(current) & mask)))
return 0;
current->ptrace_message = message;
ptrace_notify((event << 8) | SIGTRAP);
--- PTRACE/kernel/ptrace.c~03_PTRACE 2009-05-30 21:18:38.000000000 +0200
+++ PTRACE/kernel/ptrace.c 2009-05-30 22:44:41.000000000 +0200
@@ -79,7 +79,7 @@ static void ptrace_untrace(struct task_s
*/
void __ptrace_unlink(struct task_struct *child)
{
- BUG_ON(!child->ptrace);
+ BUG_ON(!task_ptrace(child));

child->ptrace = 0;
child->parent = child->real_parent;
@@ -105,7 +105,7 @@ int ptrace_check_attach(struct task_stru
* be changed by us so it's not changing right after this.
*/
read_lock(&tasklist_lock);
- if ((child->ptrace & PT_PTRACED) && child->parent == current) {
+ if (task_ptrace(child) && child->parent == current) {
ret = 0;
/*
* child->sighand can't be NULL, release_task()
@@ -203,7 +203,7 @@ int ptrace_attach(struct task_struct *ta
retval = -EPERM;
if (unlikely(task->exit_state))
goto unlock_tasklist;
- if (task->ptrace)
+ if (task_ptrace(task))
goto unlock_tasklist;

task->ptrace = PT_PTRACED;
@@ -234,7 +234,7 @@ int ptrace_traceme(void)

write_lock_irq(&tasklist_lock);
/* Are we already being traced? */
- if (!current->ptrace) {
+ if (!task_ptrace(current)) {
ret = security_ptrace_traceme(current->parent);
/*
* Check PF_EXITING to ensure ->real_parent has not passed
@@ -315,7 +315,7 @@ int ptrace_detach(struct task_struct *ch
* This child can be already killed. Make sure de_thread() or
* our sub-thread doing do_wait() didn't do release_task() yet.
*/
- if (child->ptrace) {
+ if (task_ptrace(child)) {
child->exit_code = data;
dead = __ptrace_detach(current, child);
}
@@ -402,29 +402,31 @@ int ptrace_writedata(struct task_struct

static int ptrace_setoptions(struct task_struct *child, long data)
{
- child->ptrace &= ~PT_TRACE_MASK;
+ unsigned int new_flags = 0;

if (data & PTRACE_O_TRACESYSGOOD)
- child->ptrace |= PT_TRACESYSGOOD;
+ new_flags |= PT_TRACESYSGOOD;

if (data & PTRACE_O_TRACEFORK)
- child->ptrace |= PT_TRACE_FORK;
+ new_flags |= PT_TRACE_FORK;

if (data & PTRACE_O_TRACEVFORK)
- child->ptrace |= PT_TRACE_VFORK;
+ new_flags |= PT_TRACE_VFORK;

if (data & PTRACE_O_TRACECLONE)
- child->ptrace |= PT_TRACE_CLONE;
+ new_flags |= PT_TRACE_CLONE;

if (data & PTRACE_O_TRACEEXEC)
- child->ptrace |= PT_TRACE_EXEC;
+ new_flags |= PT_TRACE_EXEC;

if (data & PTRACE_O_TRACEVFORKDONE)
- child->ptrace |= PT_TRACE_VFORK_DONE;
+ new_flags |= PT_TRACE_VFORK_DONE;

if (data & PTRACE_O_TRACEEXIT)
- child->ptrace |= PT_TRACE_EXIT;
+ new_flags |= PT_TRACE_EXIT;

+ child->ptrace &= ~PT_TRACE_MASK;
+ child->ptrace |= new_flags;
return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
}