[patch 11/14] x86, ptrace: remove ptrace_fork, use init_task instead

From: Markus Metzger
Date: Fri Mar 27 2009 - 05:23:51 EST


I introduced ptrace_fork to initialize bts tracing for a new task.

Now I've seen that there is already a ptrace_init_task() called from
tracehook that does essentially the same thing.

Remove ptrace_fork and add an arch_ variant to ptrace_init_task.


Signed-off-by: Markus Metzger <markus.t.metzger@xxxxxxxxx>
---

Index: git-tip/arch/x86/include/asm/ptrace.h
===================================================================
--- git-tip.orig/arch/x86/include/asm/ptrace.h 2009-03-27 08:18:46.000000000 +0100
+++ git-tip/arch/x86/include/asm/ptrace.h 2009-03-27 08:29:32.000000000 +0100
@@ -236,13 +236,12 @@ extern int do_set_thread_area(struct tas
struct user_desc __user *info, int can_allocate);

extern void x86_ptrace_untrace(struct task_struct *child);
-extern void x86_ptrace_fork(struct task_struct *child,
- unsigned long clone_flags);
+extern void x86_ptrace_init_task(struct task_struct *child);
extern void x86_ptrace_report_exit(long exit_code);

-#define arch_ptrace_untrace(tsk) x86_ptrace_untrace(tsk)
-#define arch_ptrace_fork(child, flags) x86_ptrace_fork(child, flags)
-#define arch_ptrace_report_exit(code) x86_ptrace_report_exit(code)
+#define arch_ptrace_untrace(tsk) x86_ptrace_untrace(tsk)
+#define arch_ptrace_init_task(child) x86_ptrace_init_task(child)
+#define arch_ptrace_report_exit(code) x86_ptrace_report_exit(code)

#endif /* __KERNEL__ */

Index: git-tip/include/linux/ptrace.h
===================================================================
--- git-tip.orig/include/linux/ptrace.h 2009-03-27 08:18:46.000000000 +0100
+++ git-tip/include/linux/ptrace.h 2009-03-27 08:29:32.000000000 +0100
@@ -154,6 +154,18 @@ static inline int ptrace_event(int mask,
return 1;
}

+#ifndef arch_ptrace_init_task
+/**
+ * arch_ptrace_init_task - initialize machine specific state for a new child
+ * @child: new child task
+ *
+ * This is called immediately after initializing the general ptrace state.
+ *
+ * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
+ */
+#define arch_ptrace_init_task(child) do { } while (0)
+#endif
+
/**
* ptrace_init_task - initialize ptrace state for a new child
* @child: new child task
@@ -174,6 +186,8 @@ static inline void ptrace_init_task(stru
child->ptrace = current->ptrace;
ptrace_link(child, current->parent);
}
+
+ arch_ptrace_init_task(child);
}

/**
@@ -326,15 +340,6 @@ static inline void user_enable_block_ste
#define arch_ptrace_untrace(task) do { } while (0)
#endif

-#ifndef arch_ptrace_fork
-/*
- * Do machine-specific work to initialize a new task.
- *
- * This is called from copy_process().
- */
-#define arch_ptrace_fork(child, clone_flags) do { } while (0)
-#endif
-
#ifndef arch_ptrace_report_exit
/**
* arch_ptrace_report_exit - Do machine specific work for exiting ptraced tasks
Index: git-tip/kernel/fork.c
===================================================================
--- git-tip.orig/kernel/fork.c 2009-03-27 08:18:46.000000000 +0100
+++ git-tip/kernel/fork.c 2009-03-27 08:29:32.000000000 +0100
@@ -1100,8 +1100,6 @@ static struct task_struct *copy_process(
#ifdef CONFIG_DEBUG_MUTEXES
p->blocked_on = NULL; /* not blocked yet */
#endif
- if (unlikely(current->ptrace))
- ptrace_fork(p, clone_flags);

/* Perform scheduler related setup. Assign this task to a CPU. */
sched_fork(p, clone_flags);
Index: git-tip/kernel/ptrace.c
===================================================================
--- git-tip.orig/kernel/ptrace.c 2009-03-27 08:18:46.000000000 +0100
+++ git-tip/kernel/ptrace.c 2009-03-27 08:29:32.000000000 +0100
@@ -27,16 +27,6 @@


/*
- * Initialize a new task whose father had been ptraced.
- *
- * Called from copy_process().
- */
-void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
-{
- arch_ptrace_fork(child, clone_flags);
-}
-
-/*
* ptrace a task: make the debugger its new parent and
* move it to the ptrace list.
*
Index: git-tip/arch/x86/kernel/ptrace.c
===================================================================
--- git-tip.orig/arch/x86/kernel/ptrace.c 2009-03-27 08:29:32.000000000 +0100
+++ git-tip/arch/x86/kernel/ptrace.c 2009-03-27 08:29:32.000000000 +0100
@@ -781,7 +781,7 @@ static int ptrace_bts_size(struct task_s
return (trace->ds.top - trace->ds.begin) / trace->ds.size;
}

-static void ptrace_bts_fork(struct task_struct *tsk)
+static void ptrace_bts_init_task(struct task_struct *tsk)
{
tsk->bts = NULL;
tsk->bts_buffer = NULL;
@@ -926,15 +926,14 @@ static void ptrace_bts_untrace(struct ta
WARN(child->bts, "leaking BTS tracer\n");
}
#else
-static inline void ptrace_bts_fork(struct task_struct *tsk) {}
+static inline void ptrace_bts_init_task(struct task_struct *tsk) {}
static inline void ptrace_bts_untrace(struct task_struct *child) {}
static inline void ptrace_bts_exit(void) {}
#endif /* CONFIG_X86_PTRACE_BTS */

-void x86_ptrace_fork(struct task_struct *child,
- unsigned long clone_flags)
+void x86_ptrace_init_task(struct task_struct *child)
{
- ptrace_bts_fork(child);
+ ptrace_bts_init_task(child);
}

void x86_ptrace_untrace(struct task_struct *child)
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