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From: Bob Liu <lliubbo@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, hughd@google.com, viro@zeniv.linux.org.uk,
	hch@lst.de, npiggin@kernel.dk, tj@kernel.org,
	dhowells@redhat.com, lethal@linux-sh.org, magnus.damm@gmail.com,
	Bob Liu <lliubbo@gmail.com>
Subject: [PATCH] ramfs: fix memleak on no-mmu arch
Date: Mon, 28 Mar 2011 13:32:35 +0800	[thread overview]
Message-ID: <1301290355-8980-1-git-send-email-lliubbo@gmail.com> (raw)

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@gmail.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;
-- 
1.6.3.3

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             reply	other threads:[~2011-03-28  5:19 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-28  5:32 Bob Liu [this message]
2011-03-29  0:02 ` [PATCH] ramfs: fix memleak on no-mmu arch Andrew Morton
2011-03-29 11:06   ` Bob Liu
2011-04-01  8:25   ` Bob Liu
2011-04-02  3:39     ` Hugh Dickins
2011-04-02  3:35   ` Hugh Dickins
2011-04-01 15:19 ` David Howells
2011-04-02  2:52 ` Hugh Dickins
  -- strict thread matches above, loose matches on Subject: below --
2011-04-13 16:45 David Howells
2011-04-13 16:45 ` David Howells

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