Subject: linux-next: build failure after merge of the vfs-brauner tree

From: Stephen Rothwell <[email-masked]>
Date: Fri, 31 Oct 2025 08:35:31 +1100

Hi all,

After merging the vfs-brauner tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:

In file included from include/linux/init.h:5,
                 from include/linux/printk.h:6,
                 from include/asm-generic/bug.h:22,
                 from arch/powerpc/include/asm/bug.h:116,
                 from include/linux/bug.h:5,
                 from arch/powerpc/include/asm/cmpxchg.h:8,
                 from arch/powerpc/include/asm/atomic.h:11,
                 from include/linux/atomic.h:7,
                 from include/linux/refcount.h:104,
                 from include/linux/ns_common.h:5,
                 from include/linux/nstree.h:5,
                 from kernel/nstree.c:3:
kernel/nstree.c: In function '__ns_tree_add_raw':
kernel/nstree.c:144:48: error: 'struct ns_tree' has no member named 'type'
  144 |         VFS_WARN_ON_ONCE(ns->ns_type != ns_tree->type);
      |                                                ^~
include/linux/build_bug.h:30:63: note: in definition of macro 'BUILD_BUG_ON_INVALID'
   30 | #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
      |                                                               ^
kernel/nstree.c:144:9: note: in expansion of macro 'VFS_WARN_ON_ONCE'
  144 |         VFS_WARN_ON_ONCE(ns->ns_type != ns_tree->type);
      |         ^~~~~~~~~~~~~~~~
kernel/nstree.c: In function '__ns_tree_remove':
kernel/nstree.c:210:48: error: 'struct ns_tree' has no member named 'type'
  210 |         VFS_WARN_ON_ONCE(ns->ns_type != ns_tree->type);
      |                                                ^~
include/linux/build_bug.h:30:63: note: in definition of macro 'BUILD_BUG_ON_INVALID'
   30 | #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
      |                                                               ^
kernel/nstree.c:210:9: note: in expansion of macro 'VFS_WARN_ON_ONCE'
  210 |         VFS_WARN_ON_ONCE(ns->ns_type != ns_tree->type);
      |         ^~~~~~~~~~~~~~~~
kernel/nstree.c: In function '__ns_tree_adjoined_rcu':
kernel/nstree.c:355:98: error: 'struct ns_tree' has no member named 'type'
  355 |         VFS_WARN_ON_ONCE(list_entry_rcu(list, struct ns_common, ns_list_node)->ns_type != ns_tree->type);
      |                                                                                                  ^~
include/linux/build_bug.h:30:63: note: in definition of macro 'BUILD_BUG_ON_INVALID'
   30 | #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
      |                                                               ^
kernel/nstree.c:355:9: note: in expansion of macro 'VFS_WARN_ON_ONCE'
  355 |         VFS_WARN_ON_ONCE(list_entry_rcu(list, struct ns_common, ns_list_node)->ns_type != ns_tree->type);
      |         ^~~~~~~~~~~~~~~~

Presumably caused by commit

  c6b288f5382b ("nstree: maintain list of owned namespaces")

I have used the vfs-brauner tree from next-20251030 for today.

-- 
Cheers,
Stephen Rothwell