header cleaning: don't include smp_lock.h when not used
[linux-3.10.git] / kernel / signal.c
index ec81def..1368e67 100644 (file)
@@ -12,7 +12,6 @@
 
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/fs.h>
@@ -24,6 +23,9 @@
 #include <linux/signal.h>
 #include <linux/capability.h>
 #include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <linux/nsproxy.h>
+
 #include <asm/param.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -453,26 +455,50 @@ 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){
@@ -583,7 +609,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
        error = -EPERM;
        if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
            && ((sig != SIGCONT) ||
-               (current->signal->session != t->signal->session))
+               (process_session(current) != process_session(t)))
            && (current->euid ^ t->suid) && (current->euid ^ t->uid)
            && (current->uid ^ t->suid) && (current->uid ^ t->uid)
            && !capable(CAP_KILL))
@@ -1093,48 +1119,28 @@ 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;
 }
 
-static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+int
+kill_proc_info(int sig, struct siginfo *info, pid_t pid)
 {
        int error;
        rcu_read_lock();
@@ -1189,8 +1195,10 @@ 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;
@@ -1205,12 +1213,14 @@ 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;
 }
 
 /*
@@ -1309,12 +1319,6 @@ 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);
@@ -1702,7 +1706,9 @@ finish_stop(int stop_count)
                read_unlock(&tasklist_lock);
        }
 
-       schedule();
+       do {
+               schedule();
+       } while (try_to_freeze());
        /*
         * Now we don't run again until continued.
         */
@@ -1877,8 +1883,12 @@ relock:
                if (sig_kernel_ignore(signr)) /* Default is nothing. */
                        continue;
 
-               /* Init gets no signals it doesn't want.  */
-               if (current == child_reaper)
+               /*
+                * Init of a pid space gets no signals it doesn't want from
+                * within that pid space. It can of course get signals from
+                * its parent pid space.
+                */
+               if (current == child_reaper(current))
                        continue;
 
                if (sig_kernel_stop(signr)) {
@@ -1897,7 +1907,7 @@ 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);
@@ -1947,7 +1957,6 @@ 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);
@@ -2274,7 +2283,7 @@ 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.
  */
@@ -2626,9 +2635,5 @@ __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
 
 void __init signals_init(void)
 {
-       sigqueue_cachep =
-               kmem_cache_create("sigqueue",
-                                 sizeof(struct sigqueue),
-                                 __alignof__(struct sigqueue),
-                                 SLAB_PANIC, NULL, NULL);
+       sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
 }