Hi all,

On Mon, 15 Feb 2021 08:05:21 +1100 Stephen Rothwell [off-list ref] wrote:

On Mon, 25 Jan 2021 17:00:54 +1100 Stephen Rothwell [off-list ref] wrote:

quoted

Today's linux-next merge of the pidfd tree got a conflict in:

  fs/namei.c

between commit:

  e36cffed20a3 ("fs: make unlazy_walk() error handling consistent")
  1e8f44f159b3 ("do_tmpfile(): don't mess with finish_open()")

from the vfs tree and commit:

  47291baa8ddf ("namei: make permission helpers idmapped mount aware")
  ba73d98745be ("namei: handle idmapped mounts in may_*() helpers")
  549c7297717c ("fs: make helpers idmap mount aware")

from the pidfd tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc fs/namei.c
index 4cae88733a5c,dbf53b325ac9..000000000000

--- a/fs/namei.c
+++ b/fs/namei.c

@@@ -1568,14 -1639,18 +1644,16 @@@ static struct dentry *lookup_slow(cons
  	return res;
  }
  
- static inline int may_lookup(struct nameidata *nd)
+ static inline int may_lookup(struct user_namespace *mnt_userns,
+ 			     struct nameidata *nd)
  {
  	if (nd->flags & LOOKUP_RCU) {
- 		int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
+ 		int err = inode_permission(mnt_userns, nd->inode,
+ 					   MAY_EXEC | MAY_NOT_BLOCK);
 -		if (err != -ECHILD)
 +		if (err != -ECHILD || !try_to_unlazy(nd))
  			return err;
 -		if (unlazy_walk(nd))
 -			return -ECHILD;
  	}
- 	return inode_permission(nd->inode, MAY_EXEC);
+ 	return inode_permission(mnt_userns, nd->inode, MAY_EXEC);
  }
  
  static int reserve_stack(struct nameidata *nd, struct path *link, unsigned seq)
@@@ -3324,9 -3453,11 +3453,9 @@@ static int do_tmpfile(struct nameidata 
  	path.dentry = child;
  	audit_inode(nd->name, child, 0);
  	/* Don't check for other permissions, the inode was just created */
- 	error = may_open(&path, 0, op->open_flag);
+ 	error = may_open(mnt_userns, &path, 0, op->open_flag);
 -	if (error)
 -		goto out2;
 -	file->f_path.mnt = path.mnt;
 -	error = finish_open(file, child, NULL);
 +	if (!error)
 +		error = vfs_open(&path, file);
  out2:
  	mnt_drop_write(path.mnt);
  out:  

With the merge window about to open, this is a reminder that this
conflict still exists.

Those vfs tree commits have also been merged into the block tree.

This is now a conflict between the pidfd tree and Linus' tree.
-- 
Cheers,
Stephen Rothwell