[PATCH 21/22] ptrace_disable: no need to disable stepping

[Oleg Nesterov]

ptrace_disable() is called when the tracee is quiescent and we
are going to untrace. This means we are going to clear ->ptrace
and wake up the tracee. Now that ptrace_stop() checks PT_ bits
and does user_disable_single_step() we can remove this code from
ptrace_disable(), it is unneeded and not utrace-friendly.

TODO: change !x86 code.

Signed-off-by: Oleg Nesterov <oleg(a)redhat.com&gt;
---
 arch/x86/kernel/ptrace.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 7ab475f..f1cdc7d 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -807,8 +807,6 @@ static int ioperm_get(struct task_struct *target,
  */
 void ptrace_disable(struct task_struct *child)
 {
-	child->ptrace &= ~(PT_SINGLE_STEP | PT_SINGLE_BLOCK);
-	user_disable_single_step(child);
 #ifdef TIF_SYSCALL_EMU
 	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 #endif
-- 
1.5.5.1