Re: [PATCH V3] glibc: fix create thread failed in old unprivileged docker

["Richard Purdie" <richard.purdie@linuxfoundation.org>]

On Sun, 2021-08-29 at 19:20 -0700, Hongxu Jia wrote:
> # Changed in V3: add missing Upstream-Status tag
> 
> Since upstream commit [d8ea0d0168 Add an internal wrapper for clone, clone2
> and clone3] applied, start a unprivileged container (docker run without
> --privileged), it creates a thread failed in container.
> 
> In commit d8ea0d0168, it calls __clone3 if HAVE_CLONE3_WAPPER is defined.  If
> __clone3 returns -1 with ENOSYS, fall back to clone or clone2.
> 
> The newest docker has fixed the issue in commit [1], but it was applied
> only on master, to backward compatibility with old docker, discussed
> with glibc maintainer [2], explicitly disable clone3 wrapper work by removing
> macro definition of HAVE_CLONE3_WRAPPER
> 
> [1] https://github.com/moby/moby/commit/9f6b562dd12ef7b1f9e2f8e6f2ab6477790a6594
> [2] https://sourceware.org/pipermail/libc-alpha/2021-August/130591.html
> 
> Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>

Just for reference, I'm going with v1 of this fix.

The reason is that I do want clone3 to work on target and I do want the wrapper
to be available. Falling back in the EPERM case is therefore easiest.

I did wonder about making the fix nativesdk specific however I decided that was
going to complicate upgrades and so on a bit too much. The v1 fix is simple
enough it can be used everywhere without too many side effects.

Cheers,

Richard