[ Upstream commit 58b6e5e8f1addd44583d61b0a03c0f5519527e35 ]
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 Signed-off-by: Sasha Levin (Microsoft) sashal@kernel.org --- 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 a7fa037b876b..a3a3d256fb0e 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -741,11 +741,17 @@ 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) { @@ -780,8 +786,10 @@ 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; }