Re: [linux-next:master 5585/5731] error[E0277]: `*const kernel::bindings::vm_uffd_ops` cannot be shared between threads safely

[Nathan Chancellor <nathan@kernel.org>]

+ relevant parties

On Thu, Mar 12, 2026 at 12:21:07PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   f90aadf1c67c8b4969d1e5e6d4fd7227adb6e4d7
> commit: 9ef1985c003ea271369c900a93f8b834119fd150 [5585/5731] Merge branch 'mm-unstable' of https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> config: x86_64-randconfig-002-20260312 (https://download.01.org/0day-ci/archive/20260312/202603121235.tpnRxFKO-lkp@intel.com/config)
> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260312/202603121235.tpnRxFKO-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202603121235.tpnRxFKO-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> error[E0277]: `*const kernel::bindings::vm_uffd_ops` cannot be shared between threads safely
>    --> drivers/android/binder/page_range.rs:146:23
>    |
>    146   | static BINDER_VM_OPS: bindings::vm_operations_struct = pin_init::zeroed();
>    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*const kernel::bindings::vm_uffd_ops` cannot be shared between threads safely
>    |
>    = help: within `kernel::bindings::vm_operations_struct`, the trait `Sync` is not implemented for `*const kernel::bindings::vm_uffd_ops`
>    note: required because it appears within the type `kernel::bindings::vm_operations_struct`
>    --> rust/bindings/bindings_generated.rs:72795:12
>    |
>    72795 | pub struct vm_operations_struct {
>    |            ^^^^^^^^^^^^^^^^^^^^
>    = note: shared static variables must have a type that implements `Sync`

I see this in next-20260313 still.

  $ cat kernel/configs/repro.config
  CONFIG_RUST=y
  CONFIG_ANDROID_BINDER_IPC_RUST=y
  CONFIG_USERFAULTFD=y

  $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 mrproper defconfig repro.config drivers/android/binder/rust_binder_main.o
  error[E0277]: `*const kernel::bindings::vm_uffd_ops` cannot be shared between threads safely
       --> drivers/android/binder/page_range.rs:146:23
        |
    146 | static BINDER_VM_OPS: bindings::vm_operations_struct = pin_init::zeroed();
        |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*const kernel::bindings::vm_uffd_ops` cannot be shared between threads safely
        |
        = help: within `kernel::bindings::vm_operations_struct`, the trait `Sync` is not implemented for `*const kernel::bindings::vm_uffd_ops`
  note: required because it appears within the type `kernel::bindings::vm_operations_struct`
       --> rust/bindings/bindings_generated.rs:71347:12
        |
  71347 | pub struct vm_operations_struct {
        |            ^^^^^^^^^^^^^^^^^^^^
        = note: shared static variables must have a type that implements `Sync`

  error: aborting due to 1 previous error

  For more information about this error, try `rustc --explain E0277`.
  ...

It looks like this is a conflict between Alice's "rust_binder: check ownership
before using vma" [1] (currently in char-misc-linus [2]) and Mike's
"userfaultfd: introduce vm_uffd_ops" [3] (currently in mm-unstable [4]),
hence why it was bisected to the -next merge commit.

[1]: https://lore.kernel.org/20260218-binder-vma-check-v2-1-60f9d695a990@google.com/
[2]: https://git.kernel.org/gregkh/char-misc/c/8ef2c15aeae07647f530d30f6daaf79eb801bcd1
[3]: https://lore.kernel.org/20260306171815.3160826-8-rppt@kernel.org/
[4]: https://git.kernel.org/akpm/mm/c/52b7ee1715b88c61fe0696db31ac90181999ec2e

Cheers,
Nathan