1 files changed, 55 insertions, 55 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 8a04869402fb..3670225ecbc0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -456,26 +456,50 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
 {
         int signr = __dequeue_signal(&tsk->pending, mask, info);
-        if (!signr)
+        if (!signr) {
                 signr = __dequeue_signal(&tsk->signal->shared_pending,
                                          mask, info);
+                /*
+                 * itimer signal ?
+                 *
+                 * itimers are process shared and we restart periodic
+                 * itimers in the signal delivery path to prevent DoS
+                 * attacks in the high resolution timer case. This is
+                 * compliant with the old way of self restarting
+                 * itimers, as the SIGALRM is a legacy signal and only
+                 * queued once. Changing the restart behaviour to
+                 * restart the timer in the signal dequeue path is
+                 * reducing the timer noise on heavy loaded !highres
+                 * systems too.
+                 */
+                if (unlikely(signr == SIGALRM)) {
+                        struct hrtimer *tmr = &tsk->signal->real_timer;
+
+                        if (!hrtimer_is_queued(tmr) &&
+                            tsk->signal->it_real_incr.tv64 != 0) {
+                                hrtimer_forward(tmr, tmr->base->get_time(),
+                                                tsk->signal->it_real_incr);
+                                hrtimer_restart(tmr);
+                        }
+                }
+        }
         recalc_sigpending_tsk(tsk);
-        if (signr && unlikely(sig_kernel_stop(signr))) {
-                /*
-                 * Set a marker that we have dequeued a stop signal.  Our
-                 * caller might release the siglock and then the pending
-                 * stop signal it is about to process is no longer in the
-                 * pending bitmasks, but must still be cleared by a SIGCONT
-                 * (and overruled by a SIGKILL).  So those cases clear this
-                 * shared flag after we've set it.  Note that this flag may
-                 * remain set after the signal we return is ignored or
-                 * handled.  That doesn't matter because its only purpose
-                 * is to alert stop-signal processing code when another
-                 * processor has come along and cleared the flag.
-                 */
-                if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
-                        tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
-        }
+        if (signr && unlikely(sig_kernel_stop(signr))) {
+                /*
+                 * Set a marker that we have dequeued a stop signal.  Our
+                 * caller might release the siglock and then the pending
+                 * stop signal it is about to process is no longer in the
+                 * pending bitmasks, but must still be cleared by a SIGCONT
+                 * (and overruled by a SIGKILL).  So those cases clear this
+                 * shared flag after we've set it.  Note that this flag may
+                 * remain set after the signal we return is ignored or
+                 * handled.  That doesn't matter because its only purpose
+                 * is to alert stop-signal processing code when another
+                 * processor has come along and cleared the flag.
+                 */
+                if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
+                        tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
+        }
         if ( signr &&
              ((info->si_code & __SI_MASK) == __SI_TIMER) &&
              info->si_sys_private){
@@ -1096,42 +1120,21 @@ int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
         return retval;
 }
 
-int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
-{
-        if (pgrp <= 0)
-                return -EINVAL;
-
-        return __kill_pgrp_info(sig, info, find_pid(pgrp));
-}
-
-int
-kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
-{
-        int retval;
-
-        read_lock(&tasklist_lock);
-        retval = __kill_pg_info(sig, info, pgrp);
-        read_unlock(&tasklist_lock);
-
-        return retval;
-}
-
 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
 {
         int error;
-        int acquired_tasklist_lock = 0;
         struct task_struct *p;
 
         rcu_read_lock();
-        if (unlikely(sig_needs_tasklist(sig))) {
+        if (unlikely(sig_needs_tasklist(sig)))
                 read_lock(&tasklist_lock);
-                acquired_tasklist_lock = 1;
-        }
+
         p = pid_task(pid, PIDTYPE_PID);
         error = -ESRCH;
         if (p)
                 error = group_send_sig_info(sig, info, p);
-        if (unlikely(acquired_tasklist_lock))
+
+        if (unlikely(sig_needs_tasklist(sig)))
                 read_unlock(&tasklist_lock);
         rcu_read_unlock();
         return error;
@@ -1193,8 +1196,10 @@ EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
 
 static int kill_something_info(int sig, struct siginfo *info, int pid)
 {
+        int ret;
+        rcu_read_lock();
         if (!pid) {
-                return kill_pg_info(sig, info, process_group(current));
+                ret = kill_pgrp_info(sig, info, task_pgrp(current));
         } else if (pid == -1) {
                 int retval = 0, count = 0;
                 struct task_struct * p;
@@ -1209,12 +1214,14 @@ static int kill_something_info(int sig, struct siginfo *info, int pid)
                         }
                 }
                 read_unlock(&tasklist_lock);
-                return count ? retval : -ESRCH;
+                ret = count ? retval : -ESRCH;
         } else if (pid < 0) {
-                return kill_pg_info(sig, info, -pid);
+                ret = kill_pgrp_info(sig, info, find_pid(-pid));
         } else {
-                return kill_proc_info(sig, info, pid);
+                ret = kill_pid_info(sig, info, find_pid(pid));
         }
+        rcu_read_unlock();
+        return ret;
 }
 
 /*
@@ -1313,12 +1320,6 @@ int kill_pid(struct pid *pid, int sig, int priv)
 EXPORT_SYMBOL(kill_pid);
 
 int
-kill_pg(pid_t pgrp, int sig, int priv)
-{
-        return kill_pg_info(sig, __si_special(priv), pgrp);
-}
-
-int
 kill_proc(pid_t pid, int sig, int priv)
 {
         return kill_proc_info(sig, __si_special(priv), pid);
@@ -1907,7 +1908,7 @@ relock:
 
                                 /* signals can be posted during this window */
 
-                                if (is_orphaned_pgrp(process_group(current)))
+                                if (is_current_pgrp_orphaned())
                                         goto relock;
 
                                 spin_lock_irq(&current->sighand->siglock);
@@ -1957,7 +1958,6 @@ EXPORT_SYMBOL(recalc_sigpending);
 EXPORT_SYMBOL_GPL(dequeue_signal);
 EXPORT_SYMBOL(flush_signals);
 EXPORT_SYMBOL(force_sig);
-EXPORT_SYMBOL(kill_pg);
 EXPORT_SYMBOL(kill_proc);
 EXPORT_SYMBOL(ptrace_notify);
 EXPORT_SYMBOL(send_sig);
@@ -2284,7 +2284,7 @@ static int do_tkill(int tgid, int pid, int sig)
  *  @pid: the PID of the thread
  *  @sig: signal to be sent
  *
- *  This syscall also checks the tgid and returns -ESRCH even if the PID
+ *  This syscall also checks the @tgid and returns -ESRCH even if the PID
  *  exists but it's not belonging to the target process anymore. This
  *  method solves the problem of threads exiting and PIDs getting reused.
  */