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authorOleg Nesterov <oleg@tv-sign.ru>2008-02-08 04:18:58 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 09:22:26 -0800
commit6b39c7bfbd1436836c0fb34c5b437fda1a7a3dd4 (patch)
tree60d3d9719eef3076527fcbf9c3cb362fe0f52d61
parent01b8b07a5d77d22e609267dcae74d15e3e9c5f13 (diff)
downloadop-kernel-dev-6b39c7bfbd1436836c0fb34c5b437fda1a7a3dd4.zip
op-kernel-dev-6b39c7bfbd1436836c0fb34c5b437fda1a7a3dd4.tar.gz
kill PT_ATTACHED
Since the patch "Fix ptrace_attach()/ptrace_traceme()/de_thread() race" commit f5b40e363ad6041a96e3da32281d8faa191597b9 we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock. This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer" which were needed to catch the "ptrace attach is in progress" case. We can also remove the flag itself since nobody else uses it. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/ptrace.h1
-rw-r--r--kernel/exit.c13
-rw-r--r--kernel/ptrace.c6
-rw-r--r--kernel/signal.c5
4 files changed, 3 insertions, 22 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 6ab8071..ebe0c17 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -67,7 +67,6 @@
#define PT_TRACE_EXEC 0x00000080
#define PT_TRACE_VFORK_DONE 0x00000100
#define PT_TRACE_EXIT 0x00000200
-#define PT_ATTACHED 0x00000400 /* parent != real_parent */
#define PT_TRACE_MASK 0x000003f4
diff --git a/kernel/exit.c b/kernel/exit.c
index eb9934a..1f2c152 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1514,18 +1514,7 @@ static int wait_task_continued(struct task_struct *p, int noreap,
static inline int my_ptrace_child(struct task_struct *p)
{
- if (!(p->ptrace & PT_PTRACED))
- return 0;
- if (!(p->ptrace & PT_ATTACHED))
- return 1;
- /*
- * This child was PTRACE_ATTACH'd. We should be seeing it only if
- * we are the attacher. If we are the real parent, this is a race
- * inside ptrace_attach. It is waiting for the tasklist_lock,
- * which we have to switch the parent links, but has already set
- * the flags in p->ptrace.
- */
- return (p->parent != p->real_parent);
+ return p->ptrace & PT_PTRACED;
}
static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 628b03a..2dc0029 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -100,8 +100,7 @@ int ptrace_check_attach(struct task_struct *child, int kill)
*/
read_lock(&tasklist_lock);
if ((child->ptrace & PT_PTRACED) && child->parent == current &&
- (!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
- && child->signal != NULL) {
+ child->signal != NULL) {
ret = 0;
spin_lock_irq(&child->sighand->siglock);
if (task_is_stopped(child))
@@ -200,8 +199,7 @@ repeat:
goto bad;
/* Go */
- task->ptrace |= PT_PTRACED | ((task->real_parent != current)
- ? PT_ATTACHED : 0);
+ task->ptrace |= PT_PTRACED;
if (capable(CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
diff --git a/kernel/signal.c b/kernel/signal.c
index 5d30ff5..6d6d1ab 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1556,11 +1556,6 @@ static inline int may_ptrace_stop(void)
{
if (!likely(current->ptrace & PT_PTRACED))
return 0;
-
- if (unlikely(current->parent == current->real_parent &&
- (current->ptrace & PT_ATTACHED)))
- return 0;
-
/*
* Are we in the middle of do_coredump?
* If so and our tracer is also part of the coredump stopping
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