Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[~andy/linux] / kernel / signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index d52e82cd62bbf8d60f01d47b3c201f1ada18d998..d7f70aed1cc0fca14dcfa15e36cd7af326f62d74 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1251,18 +1251,25 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
 {
        struct sighand_struct *sighand;
 
-       rcu_read_lock();
        for (;;) {
+               local_irq_save(*flags);
+               rcu_read_lock();
                sighand = rcu_dereference(tsk->sighand);
-               if (unlikely(sighand == NULL))
+               if (unlikely(sighand == NULL)) {
+                       rcu_read_unlock();
+                       local_irq_restore(*flags);
                        break;
+               }
 
-               spin_lock_irqsave(&sighand->siglock, *flags);
-               if (likely(sighand == tsk->sighand))
+               spin_lock(&sighand->siglock);
+               if (likely(sighand == tsk->sighand)) {
+                       rcu_read_unlock();
                        break;
-               spin_unlock_irqrestore(&sighand->siglock, *flags);
+               }
+               spin_unlock(&sighand->siglock);
+               rcu_read_unlock();
+               local_irq_restore(*flags);
        }
-       rcu_read_unlock();
 
        return sighand;
 }
@@ -1650,7 +1657,6 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
                 * it, just use SIG_IGN instead).
                 */
                autoreap = true;
-               tsk->exit_signal = -1;
                if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
                        sig = 0;
        }
@@ -1760,15 +1766,6 @@ static int sigkill_pending(struct task_struct *tsk)
                sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
 }
 
-/*
- * Test whether the target task of the usual cldstop notification - the
- * real_parent of @child - is in the same group as the ptracer.
- */
-static bool real_parent_is_ptracer(struct task_struct *child)
-{
-       return same_thread_group(child->parent, child->real_parent);
-}
-
 /*
  * This must be called with current->sighand->siglock held.
  *
@@ -1849,7 +1846,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
                 * separately unless they're gonna be duplicates.
                 */
                do_notify_parent_cldstop(current, true, why);
-               if (gstop_done && !real_parent_is_ptracer(current))
+               if (gstop_done && ptrace_reparented(current))
                        do_notify_parent_cldstop(current, false, why);
 
                /*
@@ -2094,12 +2091,17 @@ static void do_jobctl_trap(void)
 static int ptrace_signal(int signr, siginfo_t *info,
                         struct pt_regs *regs, void *cookie)
 {
-       if (!current->ptrace)
-               return signr;
-
        ptrace_signal_deliver(regs, cookie);
-
-       /* Let the debugger run.  */
+       /*
+        * We do not check sig_kernel_stop(signr) but set this marker
+        * unconditionally because we do not know whether debugger will
+        * change signr. This flag has no meaning unless we are going
+        * to stop after return from ptrace_stop(). In this case it will
+        * be checked in do_signal_stop(), we should only stop if it was
+        * not cleared by SIGCONT while we were sleeping. See also the
+        * comment in dequeue_signal().
+        */
+       current->jobctl |= JOBCTL_STOP_DEQUEUED;
        ptrace_stop(signr, CLD_TRAPPED, 0, info);
 
        /* We're back.  Did the debugger cancel the sig?  */
@@ -2155,7 +2157,6 @@ relock:
         * the CLD_ si_code into SIGNAL_CLD_MASK bits.
         */
        if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
-               struct task_struct *leader;
                int why;
 
                if (signal->flags & SIGNAL_CLD_CONTINUED)
@@ -2176,13 +2177,11 @@ relock:
                 * a duplicate.
                 */
                read_lock(&tasklist_lock);
-
                do_notify_parent_cldstop(current, false, why);
 
-               leader = current->group_leader;
-               if (leader->ptrace && !real_parent_is_ptracer(leader))
-                       do_notify_parent_cldstop(leader, true, why);
-
+               if (ptrace_reparented(current->group_leader))
+                       do_notify_parent_cldstop(current->group_leader,
+                                               true, why);
                read_unlock(&tasklist_lock);
 
                goto relock;
@@ -2206,7 +2205,7 @@ relock:
                if (!signr)
                        break; /* will return 0 */
 
-               if (signr != SIGKILL) {
+               if (unlikely(current->ptrace) && signr != SIGKILL) {
                        signr = ptrace_signal(signr, info,
                                              regs, cookie);
                        if (!signr)
@@ -2482,7 +2481,7 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
 /**
  *  sys_rt_sigprocmask - change the list of currently blocked signals
  *  @how: whether to add, remove, or set signals
- *  @set: stores pending signals
+ *  @nset: stores pending signals
  *  @oset: previous value of signal mask if non-null
  *  @sigsetsize: size of sigset_t type
  */