On Thu, Jan 02, 2020 at 06:24:06PM +0100, Amanieu d'Antras wrote:
The clone3 syscall is currently broken when used with CLONE_SETTLS on all architectures that don't have an implementation of copy_thread_tls. The old copy_thread function handles CLONE_SETTLS by reading the new TLS value from pt_regs containing the clone syscall parameters. Since clone3 passes the TLS value in clone_args, this results in the TLS register being initialized to a garbage value.
This patch series implements copy_thread_tls on all architectures that currently define __ARCH_WANT_SYS_CLONE3 and adds a compile-time check to ensure that any architecture that enables clone3 in the future also implements copy_thread_tls.
I have also included a minor fix for the arm64 uapi headers which caused __NR_clone3 to be missing from the exported user headers.
I have only tested this on arm64, but the copy_thread_tls implementations for the various architectures are fairly straightforward.
I've picked up this series and moved it into https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=clo...
If I hear no objections I'll merge into into my fixes tree today or tomorrow.
Thanks! Christian