Commit 15568299 authored by Mike Kravetz's avatar Mike Kravetz Committed by Linus Torvalds

hugetlbfs: prevent filesystem stacking of hugetlbfs

syzbot found issues with having hugetlbfs on a union/overlay as reported
in [1].  Due to the limitations (no write) and special functionality of
hugetlbfs, it does not work well in filesystem stacking.  There are no
know use cases for hugetlbfs stacking.  Rather than making modifications
to get hugetlbfs working in such environments, simply prevent stacking.

[1] https://lore.kernel.org/linux-mm/000000000000b4684e05a2968ca6@google.com/

Reported-by: syzbot+d6ec23007e951dadf3de@syzkaller.appspotmail.com
Suggested-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Colin Walters <walters@verbum.org>
Link: http://lkml.kernel.org/r/80f869aa-810d-ef6c-8888-b46cee135907@oracle.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 619b5b46
......@@ -1364,6 +1364,12 @@ hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_magic = HUGETLBFS_MAGIC;
sb->s_op = &hugetlbfs_ops;
sb->s_time_gran = 1;
/*
* Due to the special and limited functionality of hugetlbfs, it does
* not work well as a stacking filesystem.
*/
sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
if (!sb->s_root)
goto out_free;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment