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Date: Wed, 13 Apr 2011 17:45:21 +0100
From: David Howells <dhowells@...hat.com>
To: torvalds@...l.org, akpm@...ux-foundation.org
Cc: linux-mm@...ck.org, uclinux-dev@...inux.org,
linux-kernel@...r.kernel.org, Bob Liu <lliubbo@...il.com>,
Hugh Dickins <hughd@...gle.com>, stable@...nel.org,
David Howells <dhowells@...hat.com>
Subject: [PATCH] ramfs: fix memleak on no-mmu arch
From: Bob Liu <lliubbo@...il.com>
On no-mmu arch, there is a memleak duirng 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 16644 43676 0 0
-/+ buffers: 16644 43676
root:/> shmem
run ok...
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
root:/> shmem
run ok...
root:/> free
total used free shared buffers
Mem: 60320 21496 38824 0 0
-/+ buffers: 21496 38824
root:/> shmem
run ok...
root:/> free
total used free shared buffers
Mem: 60320 22692 37628 0 0
-/+ buffers: 22692 37628
root:/>
After this patch the test result is:(no memleak anymore)
root:/>
root:/> free
total used free shared buffers
Mem: 60320 16580 43740 0 0
-/+ buffers: 16580 43740
root:/> shmem
run ok...
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
root:/> shmem
run ok...
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
root:/> shmem
run ok...
root:/> free
total used free shared buffers
Mem: 60320 16668 43652 0 0
-/+ buffers: 16668 43652
root:/>
Signed-off-by: Bob Liu <lliubbo@...il.com>
Acked-by: Hugh Dickins <hughd@...gle.com>
Cc: stable@...nel.org
Signed-off-by: David Howells <dhowells@...hat.com>
---
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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