From: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Subject: mm/hugetlbfs: fix error handling when setting up mounts It is assumed that the hugetlbfs_vfsmount[] array will contain either a valid vfsmount pointer or NULL for each hstate after initialization. Changes made while converting to use fs_context broke this assumption. While fixing the hugetlbfs_vfsmount issue, it was discovered that init_hugetlbfs_fs never did correctly clean up when encountering a vfs mount error. It was found during code inspection. A small memory allocation failure would be the most likely cause of taking a error path with the bug. This is unlikely to happen as this is early init code. Link: http://lkml.kernel.org/r/94b6244d-2c24-e269-b12c-e3ba694b242d@xxxxxxxxxx Reported-by: Chengguang Xu <cgxu519@xxxxxxxxxxxx> Fixes: 32021982a324 ("hugetlbfs: Convert to fs_context") Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/hugetlbfs/inode.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) --- a/fs/hugetlbfs/inode.c~mm-hugetlbfs-fix-error-handling-when-setting-up-mounts +++ a/fs/hugetlbfs/inode.c @@ -1461,28 +1461,41 @@ static int __init init_hugetlbfs_fs(void sizeof(struct hugetlbfs_inode_info), 0, SLAB_ACCOUNT, init_once); if (hugetlbfs_inode_cachep == NULL) - goto out2; + goto out; error = register_filesystem(&hugetlbfs_fs_type); if (error) - goto out; + goto out_free; + + /* default hstate mount is required */ + mnt = mount_one_hugetlbfs(&hstates[default_hstate_idx]); + if (IS_ERR(mnt)) { + error = PTR_ERR(mnt); + goto out_unreg; + } + hugetlbfs_vfsmount[default_hstate_idx] = mnt; + /* other hstates are optional */ i = 0; for_each_hstate(h) { + if (i == default_hstate_idx) + continue; + mnt = mount_one_hugetlbfs(h); - if (IS_ERR(mnt) && i == 0) { - error = PTR_ERR(mnt); - goto out; - } - hugetlbfs_vfsmount[i] = mnt; + if (IS_ERR(mnt)) + hugetlbfs_vfsmount[i] = NULL; + else + hugetlbfs_vfsmount[i] = mnt; i++; } return 0; - out: + out_unreg: + (void)unregister_filesystem(&hugetlbfs_fs_type); + out_free: kmem_cache_destroy(hugetlbfs_inode_cachep); - out2: + out: return error; } fs_initcall(init_hugetlbfs_fs) _
