From 58b6e5e8f1addd44583d61b0a03c0f5519527e35 Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Fri, 5 Apr 2019 18:39:06 -0700 Subject: [PATCH] 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 Reviewed-by: Andrew Morton Reported-by: Yufen Yu Suggested-by: Yufen Yu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hugetlbfs/inode.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index ec32fece5e1e..9285dd4f4b1c 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -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; } -- 2.30.2