1 files changed, 72 insertions, 38 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index f006632c2ba7..da24bc1292db 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -525,7 +525,7 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
         }
         if (new_egid != old_egid)
         {
-                current->mm->dumpable = 0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         if (rgid != (gid_t) -1 ||
@@ -556,7 +556,7 @@ asmlinkage long sys_setgid(gid_t gid)
         {
                 if(old_egid != gid)
                 {
-                        current->mm->dumpable=0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->gid = current->egid = current->sgid = current->fsgid = gid;
@@ -565,7 +565,7 @@ asmlinkage long sys_setgid(gid_t gid)
         {
                 if(old_egid != gid)
                 {
-                        current->mm->dumpable=0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->egid = current->fsgid = gid;
@@ -596,7 +596,7 @@ static int set_user(uid_t new_ruid, int dumpclear)
 
         if(dumpclear)
         {
-                current->mm->dumpable = 0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         current->uid = new_ruid;
@@ -653,7 +653,7 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 
         if (new_euid != old_euid)
         {
-                current->mm->dumpable=0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         current->fsuid = current->euid = new_euid;
@@ -703,7 +703,7 @@ asmlinkage long sys_setuid(uid_t uid)
 
         if (old_euid != uid)
         {
-                current->mm->dumpable = 0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         current->fsuid = current->euid = uid;
@@ -748,7 +748,7 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
         if (euid != (uid_t) -1) {
                 if (euid != current->euid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->euid = euid;
@@ -798,7 +798,7 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
         if (egid != (gid_t) -1) {
                 if (egid != current->egid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->egid = egid;
@@ -845,7 +845,7 @@ asmlinkage long sys_setfsuid(uid_t uid)
         {
                 if (uid != old_fsuid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->fsuid = uid;
@@ -875,7 +875,7 @@ asmlinkage long sys_setfsgid(gid_t gid)
         {
                 if (gid != old_fsgid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->fsgid = gid;
@@ -894,35 +894,69 @@ asmlinkage long sys_times(struct tms __user * tbuf)
          */
         if (tbuf) {
                 struct tms tmp;
-                struct task_struct *tsk = current;
-                struct task_struct *t;
                 cputime_t utime, stime, cutime, cstime;
 
-                read_lock(&tasklist_lock);
-                utime = tsk->signal->utime;
-                stime = tsk->signal->stime;
-                t = tsk;
-                do {
-                        utime = cputime_add(utime, t->utime);
-                        stime = cputime_add(stime, t->stime);
-                        t = next_thread(t);
-                } while (t != tsk);
-
-                /*
-                 * While we have tasklist_lock read-locked, no dying thread
-                 * can be updating current->signal->[us]time.  Instead,
-                 * we got their counts included in the live thread loop.
-                 * However, another thread can come in right now and
-                 * do a wait call that updates current->signal->c[us]time.
-                 * To make sure we always see that pair updated atomically,
-                 * we take the siglock around fetching them.
-                 */
-                spin_lock_irq(&tsk->sighand->siglock);
-                cutime = tsk->signal->cutime;
-                cstime = tsk->signal->cstime;
-                spin_unlock_irq(&tsk->sighand->siglock);
-                read_unlock(&tasklist_lock);
+#ifdef CONFIG_SMP
+                if (thread_group_empty(current)) {
+                        /*
+                         * Single thread case without the use of any locks.
+                         *
+                         * We may race with release_task if two threads are
+                         * executing. However, release task first adds up the
+                         * counters (__exit_signal) before  removing the task
+                         * from the process tasklist (__unhash_process).
+                         * __exit_signal also acquires and releases the
+                         * siglock which results in the proper memory ordering
+                         * so that the list modifications are always visible
+                         * after the counters have been updated.
+                         *
+                         * If the counters have been updated by the second thread
+                         * but the thread has not yet been removed from the list
+                         * then the other branch will be executing which will
+                         * block on tasklist_lock until the exit handling of the
+                         * other task is finished.
+                         *
+                         * This also implies that the sighand->siglock cannot
+                         * be held by another processor. So we can also
+                         * skip acquiring that lock.
+                         */
+                        utime = cputime_add(current->signal->utime, current->utime);
+                        stime = cputime_add(current->signal->utime, current->stime);
+                        cutime = current->signal->cutime;
+                        cstime = current->signal->cstime;
+                } else
+#endif
+                {
+
+                        /* Process with multiple threads */
+                        struct task_struct *tsk = current;
+                        struct task_struct *t;
 
+                        read_lock(&tasklist_lock);
+                        utime = tsk->signal->utime;
+                        stime = tsk->signal->stime;
+                        t = tsk;
+                        do {
+                                utime = cputime_add(utime, t->utime);
+                                stime = cputime_add(stime, t->stime);
+                                t = next_thread(t);
+                        } while (t != tsk);
+
+                        /*
+                         * While we have tasklist_lock read-locked, no dying thread
+                         * can be updating current->signal->[us]time.  Instead,
+                         * we got their counts included in the live thread loop.
+                         * However, another thread can come in right now and
+                         * do a wait call that updates current->signal->c[us]time.
+                         * To make sure we always see that pair updated atomically,
+                         * we take the siglock around fetching them.
+                         */
+                        spin_lock_irq(&tsk->sighand->siglock);
+                        cutime = tsk->signal->cutime;
+                        cstime = tsk->signal->cstime;
+                        spin_unlock_irq(&tsk->sighand->siglock);
+                        read_unlock(&tasklist_lock);
+                }
                 tmp.tms_utime = cputime_to_clock_t(utime);
                 tmp.tms_stime = cputime_to_clock_t(stime);
                 tmp.tms_cutime = cputime_to_clock_t(cutime);
@@ -1225,7 +1259,7 @@ static void groups_sort(struct group_info *group_info)
 }
 
 /* a simple bsearch */
-static int groups_search(struct group_info *group_info, gid_t grp)
+int groups_search(struct group_info *group_info, gid_t grp)
 {
         int left, right;
 
@@ -1652,7 +1686,7 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                                 error = 1;
                         break;
                 case PR_SET_DUMPABLE:
-                        if (arg2 != 0 && arg2 != 1) {
+                        if (arg2 < 0 || arg2 > 2) {
                                 error = -EINVAL;
                                 break;
                         }