Merge branch 'linus' into cpus4096

1 files changed, 63 insertions, 36 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 82c3545596c5..954f77d7e3bc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -22,6 +22,7 @@
 #include <linux/ptrace.h>
 #include <linux/signal.h>
 #include <linux/signalfd.h>
+#include <linux/tracehook.h>
 #include <linux/capability.h>
 #include <linux/freezer.h>
 #include <linux/pid_namespace.h>
@@ -39,24 +40,21 @@
 
 static struct kmem_cache *sigqueue_cachep;
 
-static int __sig_ignored(struct task_struct *t, int sig)
+static void __user *sig_handler(struct task_struct *t, int sig)
 {
-        void __user *handler;
+        return t->sighand->action[sig - 1].sa.sa_handler;
+}
 
+static int sig_handler_ignored(void __user *handler, int sig)
+{
         /* Is it explicitly or implicitly ignored? */
-
-        handler = t->sighand->action[sig - 1].sa.sa_handler;
         return handler == SIG_IGN ||
                 (handler == SIG_DFL && sig_kernel_ignore(sig));
 }
 
 static int sig_ignored(struct task_struct *t, int sig)
 {
-        /*
-         * Tracers always want to know about signals..
-         */
-        if (t->ptrace & PT_PTRACED)
-                return 0;
+        void __user *handler;
 
         /*
          * Blocked signals are never ignored, since the
@@ -66,7 +64,14 @@ static int sig_ignored(struct task_struct *t, int sig)
         if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
                 return 0;
 
-        return __sig_ignored(t, sig);
+        handler = sig_handler(t, sig);
+        if (!sig_handler_ignored(handler, sig))
+                return 0;
+
+        /*
+         * Tracers may want to know about even ignored signals.
+         */
+        return !tracehook_consider_ignored_signal(t, sig, handler);
 }
 
 /*
@@ -129,7 +134,9 @@ void recalc_sigpending_and_wake(struct task_struct *t)
 
 void recalc_sigpending(void)
 {
-        if (!recalc_sigpending_tsk(current) && !freezing(current))
+        if (unlikely(tracehook_force_sigpending()))
+                set_thread_flag(TIF_SIGPENDING);
+        else if (!recalc_sigpending_tsk(current) && !freezing(current))
                 clear_thread_flag(TIF_SIGPENDING);
 
 }
@@ -295,12 +302,12 @@ flush_signal_handlers(struct task_struct *t, int force_default)
 
 int unhandled_signal(struct task_struct *tsk, int sig)
 {
+        void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
         if (is_global_init(tsk))
                 return 1;
-        if (tsk->ptrace & PT_PTRACED)
+        if (handler != SIG_IGN && handler != SIG_DFL)
                 return 0;
-        return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) ||
-                (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL);
+        return !tracehook_consider_fatal_signal(tsk, sig, handler);
 }
 
 
@@ -591,9 +598,6 @@ static int check_kill_permission(int sig, struct siginfo *info,
         return security_task_kill(t, info, sig, 0);
 }
 
-/* forward decl */
-static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
-
 /*
  * Handle magic process-wide effects of stop/continue signals. Unlike
  * the signal actions, these happen immediately at signal-generation
@@ -756,7 +760,8 @@ static void complete_signal(int sig, struct task_struct *p, int group)
         if (sig_fatal(p, sig) &&
             !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
             !sigismember(&t->real_blocked, sig) &&
-            (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
+            (sig == SIGKILL ||
+             !tracehook_consider_fatal_signal(t, sig, SIG_DFL))) {
                 /*
                  * This signal will be fatal to the whole group.
                  */
@@ -1323,9 +1328,11 @@ static inline void __wake_up_parent(struct task_struct *p,
 /*
  * Let a parent know about the death of a child.
  * For a stopped/continued status change, use do_notify_parent_cldstop instead.
+ *
+ * Returns -1 if our parent ignored us and so we've switched to
+ * self-reaping, or else @sig.
  */
-
-void do_notify_parent(struct task_struct *tsk, int sig)
+int do_notify_parent(struct task_struct *tsk, int sig)
 {
         struct siginfo info;
         unsigned long flags;
@@ -1396,12 +1403,14 @@ void do_notify_parent(struct task_struct *tsk, int sig)
                  */
                 tsk->exit_signal = -1;
                 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
-                        sig = 0;
+                        sig = -1;
         }
         if (valid_signal(sig) && sig > 0)
                 __group_send_sig_info(sig, &info, tsk->parent);
         __wake_up_parent(tsk, tsk->parent);
         spin_unlock_irqrestore(&psig->siglock, flags);
+
+        return sig;
 }
 
 static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
@@ -1599,7 +1608,7 @@ finish_stop(int stop_count)
          * a group stop in progress and we are the last to stop,
          * report to the parent.  When ptraced, every thread reports itself.
          */
-        if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {
+        if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) {
                 read_lock(&tasklist_lock);
                 do_notify_parent_cldstop(current, CLD_STOPPED);
                 read_unlock(&tasklist_lock);
@@ -1735,6 +1744,9 @@ relock:
                 signal->flags &= ~SIGNAL_CLD_MASK;
                 spin_unlock_irq(&sighand->siglock);
 
+                if (unlikely(!tracehook_notify_jctl(1, why)))
+                        goto relock;
+
                 read_lock(&tasklist_lock);
                 do_notify_parent_cldstop(current->group_leader, why);
                 read_unlock(&tasklist_lock);
@@ -1748,17 +1760,33 @@ relock:
                     do_signal_stop(0))
                         goto relock;
 
-                signr = dequeue_signal(current, &current->blocked, info);
-                if (!signr)
-                        break; /* will return 0 */
+                /*
+                 * Tracing can induce an artifical signal and choose sigaction.
+                 * The return value in @signr determines the default action,
+                 * but @info->si_signo is the signal number we will report.
+                 */
+                signr = tracehook_get_signal(current, regs, info, return_ka);
+                if (unlikely(signr < 0))
+                        goto relock;
+                if (unlikely(signr != 0))
+                        ka = return_ka;
+                else {
+                        signr = dequeue_signal(current, &current->blocked,
+                                               info);
 
-                if (signr != SIGKILL) {
-                        signr = ptrace_signal(signr, info, regs, cookie);
                         if (!signr)
-                                continue;
+                                break; /* will return 0 */
+
+                        if (signr != SIGKILL) {
+                                signr = ptrace_signal(signr, info,
+                                                      regs, cookie);
+                                if (!signr)
+                                        continue;
+                        }
+
+                        ka = &sighand->action[signr-1];
                 }
 
-                ka = &sighand->action[signr-1];
                 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing.  */
                         continue;
                 if (ka->sa.sa_handler != SIG_DFL) {
@@ -1806,7 +1834,7 @@ relock:
                                 spin_lock_irq(&sighand->siglock);
                         }
 
-                        if (likely(do_signal_stop(signr))) {
+                        if (likely(do_signal_stop(info->si_signo))) {
                                 /* It released the siglock.  */
                                 goto relock;
                         }
@@ -1827,7 +1855,7 @@ relock:
 
                 if (sig_kernel_coredump(signr)) {
                         if (print_fatal_signals)
-                                print_fatal_signal(regs, signr);
+                                print_fatal_signal(regs, info->si_signo);
                         /*
                          * If it was able to dump core, this kills all
                          * other threads in the group and synchronizes with
@@ -1836,13 +1864,13 @@ relock:
                          * first and our do_group_exit call below will use
                          * that value and ignore the one we pass it.
                          */
-                        do_coredump((long)signr, signr, regs);
+                        do_coredump(info->si_signo, info->si_signo, regs);
                 }
 
                 /*
                  * Death signals, no core dump.
                  */
-                do_group_exit(signr);
+                do_group_exit(info->si_signo);
                 /* NOTREACHED */
         }
         spin_unlock_irq(&sighand->siglock);
@@ -1884,7 +1912,7 @@ void exit_signals(struct task_struct *tsk)
 out:
         spin_unlock_irq(&tsk->sighand->siglock);
 
-        if (unlikely(group_stop)) {
+        if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {
                 read_lock(&tasklist_lock);
                 do_notify_parent_cldstop(tsk, CLD_STOPPED);
                 read_unlock(&tasklist_lock);
@@ -1895,7 +1923,6 @@ EXPORT_SYMBOL(recalc_sigpending);
 EXPORT_SYMBOL_GPL(dequeue_signal);
 EXPORT_SYMBOL(flush_signals);
 EXPORT_SYMBOL(force_sig);
-EXPORT_SYMBOL(ptrace_notify);
 EXPORT_SYMBOL(send_sig);
 EXPORT_SYMBOL(send_sig_info);
 EXPORT_SYMBOL(sigprocmask);
@@ -2299,7 +2326,7 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
                  *   (for example, SIGCHLD), shall cause the pending signal to
                  *   be discarded, whether or not it is blocked"
                  */
-                if (__sig_ignored(t, sig)) {
+                if (sig_handler_ignored(sig_handler(t, sig), sig)) {
                         sigemptyset(&mask);
                         sigaddset(&mask, sig);
                         rm_from_queue_full(&mask, &t->signal->shared_pending);