mm: revert mremap pud_free anti-fix

Revert commit 1ecfd53 ("mm/mremap.c: call pud_free() after fail calling pmd_alloc()"). The original code was correct: pud_alloc(), pmd_alloc(), pte_alloc_map() ensure that the pud, pmd, pt is already allocated, and seldom do they need to allocate; on failure, upper levels are freed if appropriate by the subsequent do_munmap(). Whereas commit 1ecfd53 did an unconditional pud_free() of a most-likely still-in-use pud: saved only by the near-impossiblity of pmd_alloc() failing. Signed-off-by: Hugh Dickins <[email protected]> Cc: Chen Gang <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
vieko · Oct 17, 2013 · 57a8f0c · 57a8f0c
1 parent 750e816
commit 57a8f0c
Showing 1 changed file with 1 addition and 4 deletions.
diff --git a/mm/mremap.c b/mm/mremap.c
@@ -25,7 +25,6 @@
 #include <asm/uaccess.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
-#include <asm/pgalloc.h>
 
 #include "internal.h"
 
@@ -63,10 +62,8 @@ static pmd_t *alloc_new_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
 		return NULL;
 
 	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd) {
-		pud_free(mm, pud);
+	if (!pmd)
 		return NULL;
-	}
 
 	VM_BUG_ON(pmd_trans_huge(*pmd));