Re: [PATCH 2/2] vfs: support statx(..., NULL, AT_EMPTY_PATH, ...)

[Huacai Chen <chenhuacai@kernel.org>]

Hi, Arnd,

On Mon, Jul 1, 2024 at 7:59 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Sun, Jun 30, 2024, at 04:39, Xi Ruoyao wrote:
> > On Sun, 2024-06-30 at 09:40 +0800, Huacai Chen wrote:
> >> >
> >> > Yes, both Linus and Christian hates introducing a new AT_ flag for
> >> > this.
> >> >
> >> > This patch just makes statx(fd, NULL, AT_EMPTY_PATH, ...) behave
> >> > like
> >> > statx(fd, "", AT_EMPTY_PATH, ...) instead.  NULL avoids the
> >> > performance
> >> > issue and it's also audit-able by seccomp BPF.
> >> To be honest, I still want to restore __ARCH_WANT_NEW_STAT. Because
> >> even if statx() becomes audit-able, it is still blacklisted now.
> >
> > Then patch the sandbox to allow it.
> >
> > The sandbox **must** be patched anyway or it'll be broken on all 32-bit
> > systems after 2037.  [Unless they'll unsupport all 32-bit systems before
> > 2037.]
>
> More importantly, the sandbox won't be able to support any 32-bit
> targets that support running after 2037, regardless of how long
> the sandbox supports them: if you turn off COMPAT_32BIT_TIME today
> in order to be sure those don't get called by accident, the
> fallback is immediately broken.
Would you mind if I restore newstat for LoongArch64 even if this patch exist?

Huacai

>
>       Arnd