Re: [PATCH] linux-user: Don't assume 0 is not a valid host timer_t value

[Peter Maydell]

On Tue, 26 Jul 2022 at 23:13, Jon Alduan <jon.alduan@gmail.com> wrote:
>
> Hello Peter,
>
> I can say so far, your patch solved the issue! Great thanks for that!
>
> Regarding the libc version:
> From my WSL2 Ubuntu 21.04 x86_64:
> $ ls -l /lib32/libc*
> -rwxr-xr-x 1 root root 2042632 Mar 31  2021 /lib32/libc-2.33.so
>
> My gcc version 10 does use the same libc version.
> As already mentioned, I can also reproduce this on a VM with Ubuntu 20.04 and 
> libc-2.31.
> In addition, originally, this issue was first reproduced with an own 
> buildroot RootFS and containing libc-2.28.
>
> As you see, the libcs are not that old.

So, new glibc does have a fallback timer_create() which
can return 0 as a timer_id:
 
https://elixir.bootlin.com/glibc/latest/source/sysdeps/unix/sysv/linux/timer_create.c#L150

...but it should only be using that code if the binary was
built against an old libc and then dynamically links with the
new one, which is a bit of an odd setup, and I'm not sure
why you run into it.

-- PMM