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Date: Fri, 13 Jun 2025 07:55:07 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Breno Leitao <leitao@debian.org>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>, "David S. Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo Abeni
 <pabeni@redhat.com>, David Wei <dw@davidwei.uk>, Shuah Khan
 <shuah@kernel.org>, Simon Horman <horms@kernel.org>, joe@dama.to,
 netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-kselftest@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH net-next v2 4/4] netdevsim: account dropped packet
 length in stats on queue free
Message-ID: <20250613075507.2b857743@kernel.org>
In-Reply-To: <aEw579mm+3aiXti+@gmail.com>
References: <20250613-netdevsim_stat-v2-0-98fa38836c48@debian.org>
	<20250613-netdevsim_stat-v2-4-98fa38836c48@debian.org>
	<aEw579mm+3aiXti+@gmail.com>
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On Fri, 13 Jun 2025 07:47:11 -0700 Breno Leitao wrote:
> >  static void nsim_queue_free(struct nsim_rq *rq)
> >  {
> > +	struct net_device *dev = rq->napi.dev;
> > +
> >  	hrtimer_cancel(&rq->napi_timer);
> > +	dev_dstats_rx_dropped_add(dev, rq->skb_queue.qlen);  
> 
> This is wrong and it will cause the kernel to crash in some cases, given
> we can get here with dev == NULL, in the following path:

It's probably because NAPI wasn't registered yet in some paths.
You can pass dev in from the callers, it always exists, and all 
callers have it.
-- 
pw-bot: cr