Re: [PATCH v2 1/4] um: Add pthread-based helper support

["Tiwei Bie" <tiwei.btw@antgroup.com>]

On 2025/3/18 21:06, Johannes Berg wrote:
> On Thu, 2025-03-06 at 23:07 +0800, Tiwei Bie wrote:
>> Introduce a new set of utility functions that can be used to create
>> pthread-based helpers. Helper threads created in this way will ensure
>> thread safety for errno while sharing the same memory space.
> 
> Using pthreads seemed odd, but Benjamin argues that it's the only way to
> get libc to really sort it all out, unless we never use libc syscall
> functions, which is probably kind of unreasonable? Or maybe we could?

Thanks, Benjamin! :)

Yeah, it's also the only way I've figured out so far, unless we don't use libc.

> 
> 
> Either way though,
> 
>> +#include <pthread.h>
> 
>> +	err = pthread_create(&td->handle, NULL, routine, arg);
> 
> if we're going to use pthread API, then we need to link against it?

I had the same first thought, but scripts/link-vmlinux.sh already handles it:

https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.14-rc7#n85

Regards,
Tiwei