[PATCH] task: delete task_euid()

[Gary Guo]

On 2026-02-19 12:14, Alice Ryhl wrote:
> task_euid() is a very weird operation. You can see how weird it is by
> grepping for task_euid() - binder is its only user. task_euid() obtains
> the objective effective UID - it looks at the credentials of the task
> for purposes of acting on it as an object, but then accesses the
> effective UID (which the credentials.7 man page describes as "[...] 
> used
> by the kernel to determine the permissions that the process will have
> when accessing shared resources [...]").
> 
> Since usage in Binder has now been removed, get rid of the resulting
> dead code.
> 
> Changes to the zh_CN translation was carried out with the help of
> Gemini and Google Translate.
> 
> Suggested-by: Jann Horn <jannh at google.com>
> Signed-off-by: Alice Ryhl <aliceryhl at google.com>

Reviewed-by: Gary Guo <gary at garyguo.net>

With Alex's translation suggestion applied.

Thanks,
Gary

> ---
> Depends on these two changes:
> https://lore.kernel.org/all/20260212-rust-uid-v1-1-deff4214c766@google.com/
> https://lore.kernel.org/all/20260213-binder-uid-v1-0-7b795ae05523@google.com/
> ---
>  Documentation/security/credentials.rst                    |  6 ++----
>  Documentation/translations/zh_CN/security/credentials.rst |  6 ++----
>  include/linux/cred.h                                      |  1 -
>  rust/helpers/task.c                                       |  5 -----
>  rust/kernel/task.rs                                       | 10 
> ----------
>  5 files changed, 4 insertions(+), 24 deletions(-)