Re: [PATCH v3] kernel/fork: validate exit_signal in kernel_clone()

[Christian Brauner]

On Tue, Mar 17, 2026 at 01:48:42PM +0100, Oleg Nesterov wrote:
> On 03/16, Deepanshu Kartikey wrote:
> >
> > Note that this is a user-visible change: previously, passing an invalid
> > exit_signal to clone() was silently accepted. The man page for clone()
> > does not document any defined behavior for invalid exit_signal values,
> > so rejecting them with -EINVAL is the correct behavior. It is unlikely
> > that any sane application relies on passing an invalid exit_signal.
> 
> Agreed...
> 
> > -	if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) ||
> > -		     !valid_signal(args.exit_signal)))
> > +	if (unlikely(args.exit_signal & ~((u64)CSIGNAL)))
> >  		return -EINVAL;
> 
> I guess this can die too, but OK, this needs another patch/changelog.
> 
> Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> 
> 
> Andrew, I will slightly update the changelog and resend
> do_notify_parent-sanitize-the-valid_signal-checks.patch
> in reply to this patch from Deepanshu.

I'll take this via the pidfs/kernel tree. I also have a bunch of work
touching this stuff queued there.