Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag

Christoph Hellwig
2020-09-18T13:44:12Z

On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote:
> > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */
> > - return pt_regs_trap_type(current_pt_regs()) == 0x110;
> > + return pt_regs_trap_type(current_pt_regs()) == 0x110 ||
> > + (current->flags & PF_FORCE_COMPAT);
>
> Can't say I like that approach ;-/ Reasoning about the behaviour is much
> harder when it's controlled like that - witness set_fs() shite...

I don't particularly like it either. But do you have a better idea
how to deal with io_uring vs compat tasks?