linux-kernel - Re: [patch V6 27/31] rseq: Implement fast path for exit to user

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Message-ID: <87cb6011-bf01-42bc-8dc0-aa709809b050@efficios.com>
Date: Tue, 28 Oct 2025 12:09:48 -0400
From: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To: Thomas Gleixner <tglx@...utronix.de>, LKML <linux-kernel@...r.kernel.org>
Cc: Michael Jeanson <mjeanson@...icios.com>, Jens Axboe <axboe@...nel.dk>,
 Peter Zijlstra <peterz@...radead.org>, "Paul E. McKenney"
 <paulmck@...nel.org>, x86@...nel.org, Sean Christopherson
 <seanjc@...gle.com>, Wei Liu <wei.liu@...nel.org>
Subject: Re: [patch V6 27/31] rseq: Implement fast path for exit to user

On 2025-10-27 04:45, Thomas Gleixner wrote:
[...]
> + * would be exploitable at least on x86, and also against a rouge CS

rouge -> rogue

> + * descriptor by checking the signature at the abort IP. Any fallout from
> + * invalid critical section descriptors is a user space problem. The debug
> + * case provides the full set of checks and terminates the task if a
> + * condition is not met.
> + *
> + * In case of a fault or an invalid value, this sets TIF_NOTIFY_RESUME and
> + * tells the caller to loop back into exit_to_user_mode_loop(). The rseq
> + * slow path there will handle the fail.

fail -> failure

Other than those nits:

Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com