Commit f5b7769e authored Jun 12, 2018 by Linus Torvalds

Revert "debugfs: inode: debugfs_create_dir uses mode permission from parent"



This reverts commit 95cde3c5.

The commit had good intentions, but it breaks kvm-tool and qemu-kvm.

With it in place, "lkvm run" just fails with

  Error: KVM_CREATE_VM ioctl
  Warning: Failed init: kvm__init

which isn't a wonderful error message, but bisection pinpointed the
problematic commit.

The problem is almost certainly due to the special kvm debugfs entries
created dynamically by kvm under /sys/kernel/debug/kvm/.  See
kvm_create_vm_debugfs()

Bisected-and-reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent dbee3d02

fs/debugfs/inode.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -512,9 +512,7 @@ struct dentry debugfs_create_dir(const char name, struct dentry *parent)
		if (unlikely(!inode))
		return failed_creating(dentry);

		if (!parent)
		parent = debugfs_mount->mnt_root;
		inode->i_mode = S_IFDIR \| ((d_inode(parent)->i_mode & 0770));
		inode->i_mode = S_IFDIR \| S_IRWXU \| S_IRUGO \| S_IXUGO;
		inode->i_op = &simple_dir_inode_operations;
		inode->i_fop = &simple_dir_operations;

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