From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Eric Biggers <ebiggers@kernel.org>,
linux-crypto@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] crypto: x86/aes-gcm: Disable FPU around skcipher_walk_done().
Date: Mon, 5 Aug 2024 10:21:19 +0200 [thread overview]
Message-ID: <20240805082119.n252N8l8@linutronix.de> (raw)
In-Reply-To: <Zq16_XsbZrmfnc4q@gondor.apana.org.au>
On 2024-08-03 08:34:05 [+0800], Herbert Xu wrote:
> On Fri, Aug 02, 2024 at 09:28:32AM -0700, Eric Biggers wrote:
> >
> > Note that kfree() lacks a might_sleep(), and its kerneldoc does not say that it
> > can sleep. Have you checked for other instances of this same problem? It seems
> > it would be quite common kernel-wide. Is it really necessary that kfree() takes
> > a sleepable lock on PREEMPT_RT?
>
> Agreed. kfree() gets called in all sorts of places under softirq
> context in the network stack which would presumably have the same
> issue.
>
> Please give a bit of context of when kfree started doing this.
I added "under PREEMPT_RT" in the patch description. The softirq under
PREEMPT_RT does not disable preemption so it is fully preemptible.
The other accelerated versions drop exclusive FPU access/ enable
preemption during these operations even on ARM/ ARM64.
> Cheers,
Sebastian
next prev parent reply other threads:[~2024-08-05 8:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-02 10:23 [PATCH] crypto: x86/aes-gcm: Disable FPU around skcipher_walk_done() Sebastian Andrzej Siewior
2024-08-02 16:28 ` Eric Biggers
2024-08-02 16:49 ` Eric Biggers
2024-08-05 9:02 ` Herbert Xu
2024-08-05 9:56 ` Sebastian Andrzej Siewior
2024-08-03 0:34 ` Herbert Xu
2024-08-05 8:21 ` Sebastian Andrzej Siewior [this message]
2024-08-05 8:41 ` Sebastian Andrzej Siewior
2024-08-05 17:38 ` Eric Biggers
2024-08-06 7:46 ` Sebastian Andrzej Siewior
2024-08-03 0:37 ` Herbert Xu
2024-08-05 9:34 ` Sebastian Andrzej Siewior
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