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From: Oliver Neukum <oneukum@suse.com>
To: "Ömer Mete Kaya" <omermetekaya0@gmail.com>, netdev@vger.kernel.org
Cc: oneukum@suse.com, andrew+netdev@lunn.ch, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzbot+04cd90bb99c6ef81a65d@syzkaller.appspotmail.com
Subject: Re: [PATCH net v2] usbnet: fix smp_processor_id() use in preemptible context
Date: Mon, 7 Sep 2026 13:38:53 +0200	[thread overview]
Message-ID: <6e0dbfed-cadd-4274-8165-886725413d0f@suse.com> (raw)
In-Reply-To: <20260905224553.595766-1-omermetekaya0@gmail.com>



On 06.09.26 00:45, Ömer Mete Kaya wrote:
> usbnet_skb_return() and tx_complete() call this_cpu_ptr() before
> disabling IRQs, which triggers a BUG when running with PREEMPT_FULL:
> 
>    BUG: using smp_processor_id() in preemptible code in tx_complete
> 
> Fix by saving IRQs first with local_irq_save(), then calling
> this_cpu_ptr() and using the non-irqsave variants of u64_stats
> update helpers, since IRQs are already disabled at that point.

Hi,

thank you for the patch. However, if the problem is preemption,
when not simply preempt_disable()/peempt_enable()?
Why is it necessary to switch off interrupts?

	Regards
		Oliver


  reply	other threads:[~2026-09-07 11:38 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-03 16:54 [PATCH] usbnet: fix smp_processor_id() use in preemptible context Ömer Mete Kaya
2026-09-05 22:45 ` [PATCH net v2] " Ömer Mete Kaya
2026-09-07 11:38   ` Oliver Neukum [this message]
2026-09-07 18:52     ` Ömer Mete Kaya
2026-09-07 20:23       ` David Laight
2026-09-07 21:45         ` [PATCH net v4] " Ömer Mete Kaya
2026-09-09 21:47           ` netdev-bot+sashiko
2026-09-10  9:01             ` David Laight
2026-09-07 19:05     ` [PATCH] " Ömer Mete Kaya
2026-09-08  3:43   ` [PATCH net v2] " netdev-bot+sashiko

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