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From: Paolo Abeni <pabeni@redhat.com>
To: Yuyang Huang <yuyanghuang@google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	David Ahern <dsahern@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	Ido Schimmel <idosch@nvidia.com>,
	Jakub Kicinski <kuba@kernel.org>, Simon Horman <horms@kernel.org>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 1/2] ipv4: igmp: annotate data-races around in_dev->mc_count
Date: Thu, 4 Jun 2026 11:11:30 +0200	[thread overview]
Message-ID: <95adff35-ee56-49d3-8567-382ac17810b3@redhat.com> (raw)
In-Reply-To: <20260531030705.3754389-2-yuyanghuang@google.com>

On 5/31/26 5:07 AM, Yuyang Huang wrote:
> @@ -1922,7 +1923,7 @@ void ip_mc_destroy_dev(struct in_device *in_dev)
>  
>  	while ((i = rtnl_dereference(in_dev->mc_list)) != NULL) {
>  		in_dev->mc_list = i->next_rcu;
> -		in_dev->mc_count--;
> +		WRITE_ONCE(in_dev->mc_count, in_dev->mc_count - 1);
>  		ip_mc_clear_src(i);
>  		ip_ma_put(i);

The patch LGTM, but note that sashiko has identified a pre-existing
issue which could deserve a follow-up:

https://sashiko.dev/#/patchset/20260531030705.3754389-1-yuyanghuang%40google.com

/P

>  	}
> @@ -2974,7 +2975,9 @@ static int igmp_mc_seq_show(struct seq_file *seq, void *v)
>  
>  		if (rcu_access_pointer(state->in_dev->mc_list) == im) {
>  			seq_printf(seq, "%d\t%-10s: %5d %7s\n",
> -				   state->dev->ifindex, state->dev->name, state->in_dev->mc_count, querier);
> +				   state->dev->ifindex, state->dev->name,
> +				   READ_ONCE(state->in_dev->mc_count),
> +				   querier);
>  		}
>  
>  		delta = im->timer.expires - jiffies;


  reply	other threads:[~2026-06-04  9:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-31  3:07 [PATCH net-next 0/2] ipv4: igmp: annotate diagnostic procfs data races Yuyang Huang
2026-05-31  3:07 ` [PATCH 1/2] ipv4: igmp: annotate data-races around in_dev->mc_count Yuyang Huang
2026-06-04  9:11   ` Paolo Abeni [this message]
2026-06-04  9:15     ` Paolo Abeni
2026-06-04 10:17       ` Ido Schimmel
2026-06-04 10:19   ` Ido Schimmel
2026-06-04 11:41     ` Yuyang Huang
2026-05-31  3:07 ` [PATCH 2/2] ipv4: igmp: annotate data-races around timer-related fields Yuyang Huang
2026-06-04 10:20   ` Ido Schimmel
2026-06-04 11:35     ` Yuyang Huang

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