proc: use mm_access() instead of ptrace_may_access()
mm_access() handles this much better, and avoids some race conditions.
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index cca635d..155dee6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2022,11 +2022,8 @@
if (!task)
goto out_notask;
- if (!ptrace_may_access(task, PTRACE_MODE_READ))
- goto out;
-
- mm = get_task_mm(task);
- if (!mm)
+ mm = mm_access(task, PTRACE_MODE_READ);
+ if (IS_ERR_OR_NULL(mm))
goto out;
if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
