| From | Paul Gortmaker <> | Subject | [34-longterm 062/196] ramfs: fix memleak on no-mmu arch | Date | Mon, 12 Mar 2012 20:19:35 -0400 |
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From: Bob Liu <lliubbo@gmail.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit b836aec53e2bce71de1d5415313380688c851477 upstream.
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 <lliubbo@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/ramfs/file-nommu.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c index 5ea4ad8..e9f6f9b 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; -- 1.7.9.3
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