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Date: Tue, 28 Nov 2023 21:58:54 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: "Maciej W. Rozycki" <macro@orcam.me.uk>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Subject: Re: mips: question about switch_to()->__sanitize_fcr31()
Message-ID: <20231128205854.GA29462@redhat.com>
References: <20231121135220.GA952@redhat.com>
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ping.

On 11/21, Oleg Nesterov wrote:
>
> Hello,
>
> I know absolutely nothing about arch/mips, I can't even find the
> definition of "current" or the caller of switch_to().
>
> So, __sanitize_fcr31() is called by switch_to() and it does
> force_fcr31_sig(fcr31, pc, next).
>
> Was "current" already updated at this stage so that next == current?
>
>
> Why I am asking. I want to add
>
> 	// otherwise the usage of ->siglock is not safe
> 	WARN_ON(!(t == current || task_is_traced(t)));
>
> into force_sig_info_to_task() and simplify it a bit, but I don't
> know if "t == current" is already true at the start of switch_to().
>
>
> Thanks,
>
> Oleg.