mremap: don't do mm_populate(new_addr) on failure

move_vma() sets *locked even if move_page_tables() or ->mremap() fails,
change sys_mremap() to check "ret & ~PAGE_MASK".

I think we should simply remove the VM_LOCKED code in move_vma(), that is
why this patch doesn't change move_vma().  But this needs more cleanups.

Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Benjamin LaHaise <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Laurent Dufour <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/mremap.c b/mm/mremap.c
index 3310378bb60f77a8515bfbf1c53d17849bddabc0..7dcf7b42068e66f59a2c4444c4a39c8851ee186e 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -578,8 +578,10 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
                ret = move_vma(vma, addr, old_len, new_len, new_addr, &locked);
        }
 out:
-       if (ret & ~PAGE_MASK)
+       if (ret & ~PAGE_MASK) {
                vm_unacct_memory(charged);
+               locked = 0;
+       }
        up_write(&current->mm->mmap_sem);
        if (locked && new_len > old_len)
                mm_populate(new_addr + old_len, new_len - old_len);