Re: [PATCH v10 1/5] nptl: Add __raise_direct

[Florian Weimer <fweimer@redhat.com>]

* Adhemerval Zanella:

> diff --git a/sysdeps/unix/sysv/linux/raise_direct.c b/sysdeps/unix/sysv/linux/raise_direct.c
> new file mode 100644
> index 00000000000..d38bd10817a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/raise_direct.c
> @@ -0,0 +1,29 @@
> +/* Internal function to send a signal to itself.  Linux version.
> +   Copyright (C) 2026 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <sysdep.h>
> +#include <pthread.h>
> +#include <unistd.h>
> +
> +int
> +__raise_direct (int signo)
> +{
> +  pid_t tid = INTERNAL_SYSCALL_CALL (gettid);
> +  int ret = INTERNAL_SYSCALL_CALL (tkill, tid, signo);
> +  return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO (ret) : 0;
> +}

The comment about not using the cached TID from the TCB was lost.
I suggest to add this comment to the implementation here.

Is the change from tgkill to tkill safe from a seccomp filters
perspective?  The manual page says: “Avoid using this system call.”
At the very least, you should mention this change in the commit message.

Thanks,
Florian