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Subject[PATCH 1/5] exit: wait: cleanup the ptrace_reparented() checks
Now that EXIT_DEAD is the terminal state we can kill "int traced"
variable and check "state == EXIT_DEAD" instead to cleanup the code.
In particular, this way it is clear that the check obviously doesn't
need tasklist_lock.

Also fix the type of "unsigned long state", "long" was always wrong
although this doesn't matter because cmpxchg/xchg uses typeof(*ptr).

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/exit.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index ee5399b..0511f1d 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -973,8 +973,7 @@ static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,
*/
static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
{
- unsigned long state;
- int retval, status, traced;
+ int state, retval, status;
pid_t pid = task_pid_vnr(p);
uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
struct siginfo __user *infop;
@@ -997,19 +996,18 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
}
return wait_noreap_copyout(wo, p, pid, uid, why, status);
}
-
- traced = ptrace_reparented(p);
/*
* Move the task's state to DEAD/TRACE, only one thread can do this.
*/
- state = traced && thread_group_leader(p) ? EXIT_TRACE : EXIT_DEAD;
+ state = ptrace_reparented(p) && thread_group_leader(p) ?
+ EXIT_TRACE : EXIT_DEAD;
if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
return 0;
+
/*
- * It can be ptraced but not reparented, check
- * thread_group_leader() to filter out sub-threads.
+ * Check thread_group_leader() to exclude the traced sub-threads.
*/
- if (likely(!traced) && thread_group_leader(p)) {
+ if (state == EXIT_DEAD && thread_group_leader(p)) {
struct signal_struct *psig;
struct signal_struct *sig;
unsigned long maxrss;
--
1.5.5.1


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