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From:   Thomas Gleixner <tglx@linutronix.de>
To:     "Eric W. Biederman" <ebiederm@xmission.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        Oleg Nesterov <oleg@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        Ben Segall <bsegall@google.com>,
        Borislav Petkov <bp@alien8.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Mel Gorman <mgorman@suse.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH] signal/x86: Delay calling signals in atomic
In-Reply-To: <8735j2xigt.fsf@email.froward.int.ebiederm.org>
References: <Ygq5aBB/qMQw6aP5@linutronix.de>
 <8735j2xigt.fsf@email.froward.int.ebiederm.org>
Date:   Mon, 28 Mar 2022 18:28:44 +0200
Message-ID: <87tubif3cz.ffs@tglx>
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On Mon, Mar 28 2022 at 09:25, Eric W. Biederman wrote:
> Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes:
> Further this code is buggy.  TIF_NOTIFY_RESUME is not the correct
> flag to set to enter into exit_to_usermode_loop.  TIF_NOTIFY_RESUME is
> about that happens after signal handling.  This very much needs to be
> TIF_SIGPENDING with recalc_sigpending and friends updated to know about
> "task->force_info".
>
> Does someone own this problem?  Can that person please fix this
> properly?
>
> I really don't think it is going to be maintainable for PREEMPT_RT to
> maintain a separate signal delivery path for faults from the rest of
> linux.

Fair enough. Let me queue a revert and go back to the drawing board.

Thanks,

        tglx