From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta1.migadu.com (out-186.mta1.migadu.com [95.215.58.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 586403CC310 for ; Fri, 22 May 2026 10:38:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779446320; cv=none; b=W8mi9hPv81JMsZRevWH20k5qZKYbEqt7BeeqXzfRuPx1yxCdcGVJAPYQSjr67M9jQJ9OwgTfJrK2r930W1R3XmVN/ZY41+qHtTftHv4LbNmme6aEBaiS7k+aCPr8PmVqyDbTWn/yJ1q230BldipeLvJ5B/M//QJdnJdcaz/kMAc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779446320; c=relaxed/simple; bh=UvYFNm8iymtli/Qya5etIo7DPsCtz1s3Shp9M/9yYOg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UglL4V3DA56u2+cgWGHWxfzU7oVu8jHWs1IuzBfb1DKyFJm7Vys+vOu5I8kdb21ZUBqC6zkduaXpMXSR60A54NZ26vVboMEy41teDsO14W2Gj36mNwHG0MVj8rThWi8eAGg2w6LS2O4lf6w6xDzyP+GpGbYlvhiyGGzSV4s+V2k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=lArq+iMh; arc=none smtp.client-ip=95.215.58.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="lArq+iMh" Message-ID: <186b4a77-3e34-4a87-9910-a9c5a756c766@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1779446307; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UvYFNm8iymtli/Qya5etIo7DPsCtz1s3Shp9M/9yYOg=; b=lArq+iMhI4erBdPxJn2Mo1jrk/I8AkDb29CUKG/hWKEiZTPgkw5c1MMj1NmAM/W8dK9lsD tQj/exqcWek7ZU6ehhRyi63ylCYCCSWqr/K8iurX6X4gggPmeB/wRBOebzN4p6uLxI4aO8 w6/jYZpbirHkhARx/I6xIRZ6FBaFm30= Date: Fri, 22 May 2026 18:38:12 +0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next v2] ipv4: igmp: annotate data-races around im->users To: Yuyang Huang Cc: Jiayuan Chen , "David S. Miller" , David Ahern , Eric Dumazet , Ido Schimmel , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-kernel@vger.kernel.org, netdev@vger.kernel.org References: <20260522093906.39764-1-sigefriedhyy@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Jiayuan Chen In-Reply-To: <20260522093906.39764-1-sigefriedhyy@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 5/22/26 5:39 PM, Yuyang Huang wrote: > /proc/net/igmp walks IPv4 multicast memberships under RCU and > prints im->users without holding RTNL, while multicast join and leave > paths update the field while holding RTNL. Annotate this intentional > lockless snapshot with READ_ONCE() and the matching writers with > WRITE_ONCE(). > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Yuyang Huang Reviewed-by: Jiayuan Chen