diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-02-08 04:18:58 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-08 09:22:26 -0800 |
| commit | 6b39c7bfbd1436836c0fb34c5b437fda1a7a3dd4 (patch) | |
| tree | 60d3d9719eef3076527fcbf9c3cb362fe0f52d61 | |
| parent | 01b8b07a5d77d22e609267dcae74d15e3e9c5f13 (diff) | |
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.h | 1 | ||||
| -rw-r--r-- | kernel/exit.c | 13 | ||||
| -rw-r--r-- | kernel/ptrace.c | 6 | ||||
| -rw-r--r-- | kernel/signal.c | 5 |
4 files changed, 3 insertions, 22 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 6ab80714a916..ebe0c17039cf 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 eb9934a82fc1..1f2c15297f2d 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 628b03ab88a5..2dc00298e678 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 5d30ff561847..6d6d1ab39e7e 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 |