commit: b836aec53e2bce71de1d5415313380688c851477
From: Bob Liu <lliu...@gmail.com>
Date: Thu, 14 Apr 2011 15:22:20 -0700
Subject: [PATCH] ramfs: fix memleak on no-mmu arch

On no-mmu arch, there is a memleak during shmem test.  The cause of this
memleak is ramfs_nommu_expand_for_mapping() added page refcount to 2
which makes iput() can't free that pages.

The simple test file is like this:

  int main(void)
  {
        int i;
        key_t k = ftok("/etc", 42);

        for ( i=0; i<100; ++i) {
                int id = shmget(k, 10000, 0644|IPC_CREAT);
                if (id == -1) {
                        printf("shmget error\n");
                }
                if(shmctl(id, IPC_RMID, NULL ) == -1) {
                        printf("shm  rm error\n");
                        return -1;
                }
        }
        printf("run ok...\n");
        return 0;
  }

And the result:

  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        17912        42408            0            0
  -/+ buffers:              17912        42408
  root:/> shmem
  run ok...
  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        19096        41224            0            0
  -/+ buffers:              19096        41224
  root:/> shmem
  run ok...
  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        20296        40024            0            0
  -/+ buffers:              20296        40024
  ...

After this patch the test result is:(no memleak anymore)

  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        16668        43652            0            0
  -/+ buffers:              16668        43652
  root:/> shmem
  run ok...
  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        16668        43652            0            0
  -/+ buffers:              16668        43652

Signed-off-by: Bob Liu <lliu...@gmail.com>
Acked-by: Hugh Dickins <hu...@google.com>
Signed-off-by: David Howells <dhowe...@redhat.com>
Cc: <sta...@kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
---
 fs/ramfs/file-nommu.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 9eead2c..fbb0b47 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -112,6 +112,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, 
size_t newsize)
                SetPageDirty(page);
 
                unlock_page(page);
+               put_page(page);
        }
 
        return 0;

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