Merge commit 'c104f1fa1ecf4ee0fc06e31b1f77630b2551be81' into stable/for-linus-3.4

* commit 'c104f1fa1ecf4ee0fc06e31b1f77630b2551be81': (14566 commits)
  cpufreq: OMAP: fix build errors: depends on ARCH_OMAP2PLUS
  sparc64: Eliminate obsolete __handle_softirq() function
  sparc64: Fix bootup crash on sun4v.
  kconfig: delete last traces of __enabled_ from autoconf.h
  Revert "kconfig: fix __enabled_ macros definition for invisible and un-selected symbols"
  kconfig: fix IS_ENABLED to not require all options to be defined
  irq_domain: fix type mismatch in debugfs output format
  staging: android: fix mem leaks in __persistent_ram_init()
  staging: vt6656: Don't leak memory in drivers/staging/vt6656/ioctl.c::private_ioctl()
  staging: iio: hmc5843: Fix crash in probe function.
  panic: fix stack dump print on direct call to panic()
  drivers/rtc/rtc-pl031.c: enable clock on all ST variants
  Revert "mm: vmscan: fix misused nr_reclaimed in shrink_mem_cgroup_zone()"
  hugetlb: fix race condition in hugetlb_fault()
  drivers/rtc/rtc-twl.c: use static register while reading time
  drivers/rtc/rtc-s3c.c: add placeholder for driver private data
  drivers/rtc/rtc-s3c.c: fix compilation error
  MAINTAINERS: add PCDP console maintainer
  memcg: do not open code accesses to res_counter members
  drivers/rtc/rtc-efi.c: fix section mismatch warning
  ...

1 files changed, 9 insertions, 14 deletions

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index e920aa3ce104..c20ff48994c2 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -298,23 +298,18 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,
                 goto free_proc_pages;
         }
 
-        task_lock(task);
-        if (__ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
-                task_unlock(task);
-                rc = -EPERM;
-                goto put_task_struct;
-        }
-        mm = task->mm;
-
-        if (!mm || (task->flags & PF_KTHREAD)) {
-                task_unlock(task);
-                rc = -EINVAL;
+        mm = mm_access(task, PTRACE_MODE_ATTACH);
+        if (!mm || IS_ERR(mm)) {
+                rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
+                /*
+                 * Explicitly map EACCES to EPERM as EPERM is a more a
+                 * appropriate error code for process_vw_readv/writev
+                 */
+                if (rc == -EACCES)
+                        rc = -EPERM;
                 goto put_task_struct;
         }
 
-        atomic_inc(&mm->mm_users);
-        task_unlock(task);
-
         for (i = 0; i < riovcnt && iov_l_curr_idx < liovcnt; i++) {
                 rc = process_vm_rw_single_vec(
                         (unsigned long)rvec[i].iov_base, rvec[i].iov_len,