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@oracle.com
Reported-by: Chengguang Xu <cgxu519@mykernel.net>
Fixes: 32021982a3 ("hugetlbfs: Convert to fs_context")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Kravetz 2019-11-30 17:56:34 -08:00 committed by Linus Torvalds
parent 552546366a
commit 8fc312b32b

View File

@ -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)