x86/mm: unify init task OOM handling

Linus noticed that the "again:" versus "survive:" OOM logic for
the init task was arbitrarily different.

The 64-bit codepath is the better one, because it correctly re-lookups
the vma after having dropped the ->mmap_sem.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 9 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index ac2ad781da00..8bc5956e1af4 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -671,7 +671,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
                 goto bad_area_nosemaphore;
 
 again:
-        /* When running in the kernel we expect faults to occur only to
+        /*
+         * When running in the kernel we expect faults to occur only to
          * addresses in user space.  All other faults represent errors in the
          * kernel and should generate an OOPS.  Unfortunately, in the case of an
          * erroneous fault occurring in a code path which already holds mmap_sem
@@ -734,9 +735,6 @@ good_area:
                         goto bad_area;
         }
 
-#ifdef CONFIG_X86_32
-survive:
-#endif
         /*
          * If for any reason at all we couldn't handle the fault,
          * make sure we exit gracefully rather than endlessly redo
@@ -871,12 +869,11 @@ out_of_memory:
         up_read(&mm->mmap_sem);
         if (is_global_init(tsk)) {
                 yield();
-#ifdef CONFIG_X86_32
-                down_read(&mm->mmap_sem);
-                goto survive;
-#else
+                /*
+                 * Re-lookup the vma - in theory the vma tree might
+                 * have changed:
+                 */
                 goto again;
-#endif
         }
 
         printk("VM: killing process %s\n", tsk->comm);