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exit: wait: cleanup the ptrace_reparented() checks

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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).

[akpm@linux-foundation.org: don't make me google the C Operator Precedence table]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sterling Alexander <stalexan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-12-10 15:54:45 -08:00 committed by Linus Torvalds
parent 7f6def9f9b
commit f6507f83bc
1 changed files with 6 additions and 8 deletions
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14
kernel/exit.c
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@ -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;
@ -999,19 +998,18 @@ 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;