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hugetlbfs: fix memory leak for resv_map 

When mknod is used to create a block special file in hugetlbfs, it will
allocate an inode and kmalloc a 'struct resv_map' via resv_map_alloc().
inode->i_mapping->private_data will point the newly allocated resv_map.
However, when the device special file is opened bd_acquire() will set
inode->i_mapping to bd_inode->i_mapping.  Thus the pointer to the
allocated resv_map is lost and the structure is leaked.

Programs to reproduce:
        mount -t hugetlbfs nodev hugetlbfs
        mknod hugetlbfs/dev b 0 0
        exec 30<> hugetlbfs/dev
        umount hugetlbfs/

resv_map structures are only needed for inodes which can have associated
page allocations.  To fix the leak, only allocate resv_map for those
inodes which could possibly be associated with page allocations.

Link: http://lkml.kernel.org/r/20190401213101.16476-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Yufen Yu <yuyufen@huawei.com>
Suggested-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Mike Kravetz 2019-04-05 18:39:06 -07:00 committed by Linus Torvalds
parent fcae96ff96
commit 58b6e5e8f1
1 changed files with 14 additions and 6 deletions
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20
fs/hugetlbfs/inode.c
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@ -755,11 +755,17 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
umode_t mode, dev_t dev)
{
struct inode *inode;
struct resv_map *resv_map;
struct resv_map *resv_map = NULL;
resv_map = resv_map_alloc();
if (!resv_map)
return NULL;
/*
* Reserve maps are only needed for inodes that can have associated
* page allocations.
*/
if (S_ISREG(mode) || S_ISLNK(mode)) {
resv_map = resv_map_alloc();
if (!resv_map)
return NULL;
}
inode = new_inode(sb);
if (inode) {
@ -794,8 +800,10 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
break;
}
lockdep_annotate_inode_mutex_key(inode);
} else
kref_put(&resv_map->refs, resv_map_release);
} else {
if (resv_map)
kref_put(&resv_map->refs, resv_map_release);
}
return inode;
}