From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: tip-bot2 for Niels Pressel <tip-bot2@linutronix.de>,
linux-tip-commits@vger.kernel.org,
Niels Pressel <npressel@ethz.ch>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [tip: core/urgent] entry/rseq: Fix hard lockup on granted time slice extension
Date: Sat, 08 Aug 2026 13:23:42 +0200 [thread overview]
Message-ID: <87se4on9dt.ffs@fw13> (raw)
In-Reply-To: <20260808083635.GR687043@noisy.programming.kicks-ass.net>
On Sat, Aug 08 2026 at 10:36, Peter Zijlstra wrote:
> On Fri, Aug 07, 2026 at 11:15:19PM +0200, Thomas Gleixner wrote:
>> rseq = curr->rseq.usrptr;
>> scoped_user_rw_access(rseq, efault) {
>>
>> That's user access which requires interrupts to be enabled.
>
> Well, you can do user access with IRQs disabled just fine, you just get
> more efault.
Sure, but then you need a manual fault handler, which requires that
interrupts are enabled :)
>> So the thing [wm]e f*cked up royally was to invoke
>> hrtimer_rearm_deferred_tif() with interrupts enabled and that needs to
>> be fixed.
>>
>> Of course all of this can be figured out from the copious amount of
>> comments which got added to explain all of this magic.
>
> Bah, its spread out over too damn many functions is what :/
That and comments are missing at crucial places :(
prev parent reply other threads:[~2026-08-08 11:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-06 11:34 [PATCH v2] rseq: fix hard lockup on granted time slice extension Niels Pressel
2026-08-06 12:48 ` [tip: core/urgent] entry/rseq: Fix " tip-bot2 for Niels Pressel
2026-08-07 21:15 ` Thomas Gleixner
2026-08-08 8:36 ` Peter Zijlstra
2026-08-08 11:23 ` Thomas Gleixner [this message]
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