1 files changed, 12 insertions, 5 deletions

diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index db443221ba5b..96f77013d3f0 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -36,7 +36,7 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
 
         /* calculate task elapsed time in timespec */
         do_posix_clock_monotonic_gettime(&uptime);
-        ts = timespec_sub(uptime, current->group_leader->start_time);
+        ts = timespec_sub(uptime, tsk->start_time);
         /* rebase elapsed time to usec */
         ac_etime = timespec_to_ns(&ts);
         do_div(ac_etime, NSEC_PER_USEC);
@@ -58,7 +58,10 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
         stats->ac_uid    = tsk->uid;
         stats->ac_gid    = tsk->gid;
         stats->ac_pid    = tsk->pid;
-        stats->ac_ppid   = (tsk->parent) ? tsk->parent->pid : 0;
+        rcu_read_lock();
+        stats->ac_ppid   = pid_alive(tsk) ?
+                                rcu_dereference(tsk->real_parent)->tgid : 0;
+        rcu_read_unlock();
         stats->ac_utime  = cputime_to_msecs(tsk->utime) * USEC_PER_MSEC;
         stats->ac_stime  = cputime_to_msecs(tsk->stime) * USEC_PER_MSEC;
         stats->ac_minflt = tsk->min_flt;
@@ -77,13 +80,17 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
  */
 void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
 {
+        struct mm_struct *mm;
+
         /* convert pages-jiffies to Mbyte-usec */
         stats->coremem = jiffies_to_usecs(p->acct_rss_mem1) * PAGE_SIZE / MB;
         stats->virtmem = jiffies_to_usecs(p->acct_vm_mem1) * PAGE_SIZE / MB;
-        if (p->mm) {
+        mm = get_task_mm(p);
+        if (mm) {
                 /* adjust to KB unit */
-                stats->hiwater_rss   = p->mm->hiwater_rss * PAGE_SIZE / KB;
-                stats->hiwater_vm    = p->mm->hiwater_vm * PAGE_SIZE / KB;
+                stats->hiwater_rss   = mm->hiwater_rss * PAGE_SIZE / KB;
+                stats->hiwater_vm    = mm->hiwater_vm * PAGE_SIZE / KB;
+                mmput(mm);
         }
         stats->read_char        = p->rchar;
         stats->write_char       = p->wchar;