Commit d6f2589a authored Mar 25, 2014 by Jan Kara Committed by Linus Torvalds Mar 25, 2014

fs: Avoid userspace mounting anon_inodefs filesystem



anon_inodefs filesystem is a kernel internal filesystem userspace
shouldn't mess with. Remove registration of it so userspace cannot
even try to mount it (which would fail anyway because the filesystem is
MS_NOUSER).

This fixes an oops triggered by trinity when it tried mounting
anon_inodefs which overwrote anon_inode_inode pointer while other CPU
has been in anon_inode_getfile() between ihold() and d_instantiate().
Thus effectively creating dentry pointing to an inode without holding a
reference to it.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 632b06aa

fs/anon_inodes.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -177,9 +177,6 @@ static int __init anon_inode_init(void)
		{
		int error;

		error = register_filesystem(&anon_inode_fs_type);
		if (error)
		goto err_exit;
		anon_inode_mnt = kern_mount(&anon_inode_fs_type);
		if (IS_ERR(anon_inode_mnt)) {
		error = PTR_ERR(anon_inode_mnt);

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