[PATCH 4.14 34/54] fs/proc/task_mmu.c: fix Locked field in /proc/pid/smaps*

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vlastimil Babka <vbabka@xxxxxxx>

commit e70cc2bd579e8a9d6d153762f0fe294d0e652ff0 upstream.

Thomas reports:
 "While looking around in /proc on my v4.14.52 system I noticed that all
  processes got a lot of "Locked" memory in /proc/*/smaps. A lot more
  memory than a regular user can usually lock with mlock().

  Commit 493b0e9d945f (in v4.14-rc1) seems to have changed the behavior
  of "Locked".

  Before that commit the code was like this. Notice the VM_LOCKED check.

           (vma->vm_flags & VM_LOCKED) ?
                (unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);

  After that commit Locked is now the same as Pss:

	  (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));

  This looks like a mistake."

Indeed, the commit has added mss->pss_locked with the correct value that
depends on VM_LOCKED, but forgot to actually use it.  Fix it.

Link: http://lkml.kernel.org/r/ebf6c7fb-fec3-6a26-544f-710ed193c154@xxxxxxx
Fixes: 493b0e9d945f ("mm: add /proc/pid/smaps_rollup")
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Reported-by: Thomas Lindroth <thomas.lindroth@xxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Daniel Colascione <dancol@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/proc/task_mmu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -850,7 +850,7 @@ static int show_smap(struct seq_file *m,
 			   mss->private_hugetlb >> 10,
 			   mss->swap >> 10,
 			   (unsigned long)(mss->swap_pss >> (10 + PSS_SHIFT)),
-			   (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
+			   (unsigned long)(mss->pss_locked >> (10 + PSS_SHIFT)));
 
 	if (!rollup_mode) {
 		arch_show_smap(m, vma);