From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 1A0531DF996 for ; Thu, 28 Aug 2025 09:19:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756372760; cv=none; b=AuYRXAHaeovIR8dYaMqukbopzHktZcFX3+HhAOpQlvFUHWSmyJkI2pxFR7D23trupBRoL0F8TaX4Xyx4uIgkiLnVrXNUPRSz8FODWb1xDY9U+QkXQzEo8oRZDCwdhQeVNzIlJtml75jwE7xxVuJjjAoApsWUuAf3Nq2hFnBJzDk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756372760; c=relaxed/simple; bh=FfoXFGeGmnpKxzS/K/q3q81DIcoMsb+Pu2BTo37S4DA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=c2wSmlYjfIkiEx2lxuS02JqTOZk6FSDaO6J1uMiz2eJsaIIegLwjWsct1AEHLTGzGaq80u5og+VALKQIjSn9oU8QYQWeFJNsb9HFbTpiR8CG77W/nlPExRgv+WuyQ8vlcjZWOOl75TVa3GeT1n9zbx67zC+xQ88hy9rg5JWYao8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=X19UdC62; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="X19UdC62" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756372758; 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=9Bp45yh3Te0X9QhLiIqLtMGTynS3AxXPNJIWRzKQFuY=; b=X19UdC6216VrRUCYeg3SfgdSUh/ANcjzIgSFqJb5Wfl/pykjqxLrRQ6NT52vSBw1lnWwlf ogn5VlL7h0CX/UiClo7hvKVQiYcJCKwkSb4HXgX5zOWSflZk0Xw/Ar+gSKyq/zpuBjbE3R 4WKrNU/wM5ew6wssrfCgf8UHZjDqKtM= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-7-vx1a2UUgPbuj1kOuezv44w-1; Thu, 28 Aug 2025 05:19:16 -0400 X-MC-Unique: vx1a2UUgPbuj1kOuezv44w-1 X-Mimecast-MFC-AGG-ID: vx1a2UUgPbuj1kOuezv44w_1756372756 Received: by mail-qk1-f199.google.com with SMTP id af79cd13be357-7e86f8f27e1so197151785a.0 for ; Thu, 28 Aug 2025 02:19:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756372756; x=1756977556; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9Bp45yh3Te0X9QhLiIqLtMGTynS3AxXPNJIWRzKQFuY=; b=fnJkQFDSjBTmpKzbHiSQNAvJxx8JPd6K0UzBP2WmQTATBT5iPPKIFfkiRC+2C/5poj CJB/ZJSUWWBf4wuuR+W7EJwJ+V59tDc7SzTRAk0S9NV/iOXoM1Hs914QylMPwY6RG0e+ KxPwjdVJvg8uuEE2ifbdzbwkeRTlkq2WK++NTMPy+Ma7HIqsCwtnx614RNSGluSIvWeQ iDwq3zDQOFKupN06XgF/bQEaQ5Ir76upXSv9vcrudMFQbMPfTxscAeYYDTFWOMVSdHci fH0mqVgIpKwsE0iPHJLBuYjymJZWur6Zbcgeu1pfjEVntwgz9aArBIO6qtVo6Th+o2hO jxAw== X-Forwarded-Encrypted: i=1; AJvYcCXMMZEhHo0mO84xioC9wA7dIHsmWUaInj7DVq2qIZ6BHWVCZY/LREtxqdH14AGvLDeQSRgTirY=@vger.kernel.org X-Gm-Message-State: AOJu0YyEqGyRuWoNA79i+qv8ZEp1/EaMhxMHoscjZ6FYDjtD7VjCmiON D+S2vSS9DuRJ6PyI3hIiQp8gEqLGEOPnnLe9rG6g0o/IwcegyoM39S2UNkvR8fnur8u9DHHn8iL xezkBgkvMdXwt5U/1FpLqpqgqkT8sSW+438PVCn1HCjKTUADNfK2/Xbcc4g== X-Gm-Gg: ASbGncsQ23XODNQTFmueTCmP6ozM5vv0VbUuqZVKagdzxRwdzQ0AxKDDjoY3XVyLA5H vaVD7XHoMqohgowMNeobl0Om3XMr08Balu/6ymYME5MQMNY9SYBmOsLSE6UFEd/jqhnn2gJO+E7 lzGX4x+Igg7v3mYwn7wvlAVSRzaE55rGJs4M9BJnL3tHdLsBctTelAQZn30Em0um6QnTISUug9c snG7gfZwNJx6X95RGCA5izeJCIZ9SBW8BCQJIufaQBVKln+A5HLSwypsBdK/aUl4zq9hiOkV4bV CIr7+iRzktwJBAcwYYtzAcRfSDMzsW+0axjXZ/A6FdDrwPc34CPGJLVDToMFseCp49WQqKPzNTL r9JfZPZnSUyc= X-Received: by 2002:a05:620a:7013:b0:7e8:7a7b:5723 with SMTP id af79cd13be357-7f58d942121mr778015685a.22.1756372756141; Thu, 28 Aug 2025 02:19:16 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHi9aA2lip4GhP2MqXoLgeWU1mVLS0aUtyXoB0MHe+cWNBrCSQkgSBeTYDleWgs/vjgtimwMg== X-Received: by 2002:a05:620a:7013:b0:7e8:7a7b:5723 with SMTP id af79cd13be357-7f58d942121mr778013985a.22.1756372755714; Thu, 28 Aug 2025 02:19:15 -0700 (PDT) Received: from ?IPV6:2a0d:3344:2712:7e10:4d59:d956:544f:d65c? ([2a0d:3344:2712:7e10:4d59:d956:544f:d65c]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7ebf3da460fsm1040835785a.62.2025.08.28.02.19.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 Aug 2025 02:19:15 -0700 (PDT) Message-ID: <147f016f-bf5e-4cb6-80a7-192db0ff62c4@redhat.com> Date: Thu, 28 Aug 2025 11:19:11 +0200 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: [PATCHv2 net] hsr: use proper locking when iterating over ports To: Hangbin Liu , netdev@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , MD Danish Anwar , Alexander Lobakin , Jaakko Karrenpalo , Fernando Fernandez Mancera , Murali Karicheri , WingMan Kwok , Stanislav Fomichev , Xiao Liang , Kuniyuki Iwashima , Johannes Berg References: <20250827093323.432414-1-liuhangbin@gmail.com> Content-Language: en-US From: Paolo Abeni In-Reply-To: <20250827093323.432414-1-liuhangbin@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/27/25 11:33 AM, Hangbin Liu wrote: > @@ -672,9 +672,13 @@ struct net_device *hsr_get_port_ndev(struct net_device *ndev, > struct hsr_priv *hsr = netdev_priv(ndev); > struct hsr_port *port; > > + rcu_read_lock(); > hsr_for_each_port(hsr, port) > - if (port->type == pt) > + if (port->type == pt) { > + rcu_read_unlock(); > return port->dev; This is not good enough. At this point accessing `port` could still cause UaF; The only callers, in icssg_prueth_hsr_{add,del}_mcast(), can be either under the RTNL lock or not. A safer option would be acquiring a reference on dev before releasing the rcu lock and let the caller drop such reference > + } > + rcu_read_unlock(); > return NULL; > } > EXPORT_SYMBOL(hsr_get_port_ndev); > diff --git a/net/hsr/hsr_main.c b/net/hsr/hsr_main.c > index 192893c3f2ec..eec6e20a8494 100644 > --- a/net/hsr/hsr_main.c > +++ b/net/hsr/hsr_main.c > @@ -22,9 +22,13 @@ static bool hsr_slave_empty(struct hsr_priv *hsr) > { > struct hsr_port *port; > > + rcu_read_lock(); > hsr_for_each_port(hsr, port) > - if (port->type != HSR_PT_MASTER) > + if (port->type != HSR_PT_MASTER) { > + rcu_read_unlock(); > return false; > + } > + rcu_read_unlock(); > return true; > } AFAICS the only caller of this helper is under the RTNL lock > @@ -134,9 +138,13 @@ struct hsr_port *hsr_port_get_hsr(struct hsr_priv *hsr, enum hsr_port_type pt) > { > struct hsr_port *port; > > + rcu_read_lock(); > hsr_for_each_port(hsr, port) > - if (port->type == pt) > + if (port->type == pt) { > + rcu_read_unlock(); > return port; The above is not enough. AFAICS some/most caller are already either under the RTNL lock or the rcu lock. I think it would be better rename the hsr_for_each_port_rtnl() helper to hsr_for_each_port_rcu(), retaining the current semantic, use it here, and fix the caller as needed. It will be useful to somehow split the patch in a series, as it's already quite big and will increase even more. /P