From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 18107346A04 for ; Thu, 22 Jan 2026 20:05:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769112338; cv=none; b=n6/ZGeup+c43DTIg2IWDyfw4s8JA2erjhD7cphC8d8XTEjfMYu+IoHSCioWXHgiLnBDvdlY7gqkegSXgVgssYyivhBnCNPUOOWy5BwCbFzBGwjGetnOsuVwkQaWkWjumXoAhIjMkCAmFNjwpdjW894YThnK66rBSLAtYbDKgFls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769112338; c=relaxed/simple; bh=eWihy3VUCeEi3epkPHxvkcRSpVRAyqmLAcirtp7FW9g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ImGxY5k28w0NePXMJa7T/woWiwh37Uwq0MWY+YT+wlX1lRe1Wt0HDLNigkyGyosWmC+RTkkoAIsJdWHX/o89hO4/HZ3MrAJAQbdVBIvTK2e/1z+H8movtY4ubYG9fM/42Tt1FSh22tHiQTF0bL7nzPmd260UoBLQ85uFGBF6uaI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Clfw6A0B; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Clfw6A0B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5FA2C116C6; Thu, 22 Jan 2026 20:05:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769112336; bh=eWihy3VUCeEi3epkPHxvkcRSpVRAyqmLAcirtp7FW9g=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Clfw6A0B/gvwOxK/BZB8riW6G3sZ4O1F9MevvP7LomTQ6wkPmZA2CnZO2PUTpMvOY xVVqht+VnWtw57WkJBS+Ha+ah8ncYU3eOny2RDW/XDVe0U7leFj4bdzPlmszvNKt6Y SEVEwWdz6r1ITFo5I8FWxU6XDPJCyQmYRWbxCWCBEVGW3jEBJ34AS0aEWgj8JRPslD HfA34NeWqnWTA8mta88cvgi0xHI5bXpEEA9rUyjRyA9Pw0UDcwh0htMf91jYbQ0Co6 +R9InK2Ro1x9503zGqj89XoLUKXsi1svUymU2FyNOQ9NJUS3yl5FFoJ66YboUfA1qQ NEeYsZ3dbITTw== Message-ID: <60f5b633-d214-450c-a1ce-26df8f2d8f26@kernel.org> Date: Thu, 22 Jan 2026 13:05:34 -0700 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next] ipv4: igmp: annotate data-races around idev->mr_maxdelay Content-Language: en-US To: Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , netdev@vger.kernel.org, eric.dumazet@gmail.com References: <20260122172247.2429403-1-edumazet@google.com> From: David Ahern In-Reply-To: <20260122172247.2429403-1-edumazet@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/22/26 10:22 AM, Eric Dumazet wrote: > idev->mr_maxdelay is read and written locklessly, > add READ_ONCE()/WRITE_ONCE() annotations. > > While we are at it, make this field an u32. > > Signed-off-by: Eric Dumazet > --- > include/linux/inetdevice.h | 2 +- > net/ipv4/igmp.c | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h > index 5730ba6b1cfaff25f2b9d206722662e1e62b88fc..dccbeb25f70141982160c776f3cc727296def2b7 100644 > --- a/include/linux/inetdevice.h > +++ b/include/linux/inetdevice.h > @@ -38,11 +38,11 @@ struct in_device { > struct ip_mc_list *mc_tomb; > unsigned long mr_v1_seen; > unsigned long mr_v2_seen; > - unsigned long mr_maxdelay; > unsigned long mr_qi; /* Query Interval */ > unsigned long mr_qri; /* Query Response Interval */ > unsigned char mr_qrv; /* Query Robustness Variable */ > unsigned char mr_gq_running; > + u32 mr_maxdelay; > u32 mr_ifc_count; > struct timer_list mr_gq_timer; /* general query timer */ > struct timer_list mr_ifc_timer; /* interface change timer */ > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > index 7182f1419c2a4d4ea1e90ef6857f6af895dd2770..0adc993c211d7a3901f9a0e9ee816e7fddc598cd 100644 > --- a/net/ipv4/igmp.c > +++ b/net/ipv4/igmp.c > @@ -227,7 +227,7 @@ static void igmp_start_timer(struct ip_mc_list *im, int max_delay) > > static void igmp_gq_start_timer(struct in_device *in_dev) > { > - int tv = get_random_u32_below(in_dev->mr_maxdelay); > + int tv = get_random_u32_below(READ_ONCE(in_dev->mr_maxdelay)); u32 tv? fix that type while at it. > unsigned long exp = jiffies + tv + 2; > > if (in_dev->mr_gq_running && > @@ -1009,7 +1009,7 @@ static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb, > max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE); > if (!max_delay) > max_delay = 1; /* can't mod w/ 0 */ > - in_dev->mr_maxdelay = max_delay; > + WRITE_ONCE(in_dev->mr_maxdelay, max_delay); max_delay can also be u32; only scope creep with this patch set is fixing up igmp_mod_timer to take u32. > > /* RFC3376, 4.1.6. QRV and 4.1.7. QQIC, when the most recently > * received value was zero, use the default or statically Reviewed-by: David Ahern