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 0a1bf2c8bdcd108ac730194b7ccbbca5377f5566..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;
 }
@@ -2084,12 +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?  */
@@ -2193,7 +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)
@@ -2469,7 +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
  */