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Date: Wed, 22 Nov 2023 19:07:25 +0000
From: Simon Horman <horms@kernel.org>
To: Wen Gu <guwen@linux.alibaba.com>
Cc: wintera@linux.ibm.com, wenjia@linux.ibm.com, hca@linux.ibm.com,
	gor@linux.ibm.com, agordeev@linux.ibm.com, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	kgraul@linux.ibm.com, jaka@linux.ibm.com, borntraeger@linux.ibm.com,
	svens@linux.ibm.com, alibuda@linux.alibaba.com,
	tonylu@linux.alibaba.com, raspl@linux.ibm.com,
	schnelle@linux.ibm.com, linux-s390@vger.kernel.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 5/7] net/smc: compatible with 128-bits extend
 GID of virtual ISM device
Message-ID: <20231122190725.GB6731@kernel.org>
References: <1700402277-93750-1-git-send-email-guwen@linux.alibaba.com>
 <1700402277-93750-6-git-send-email-guwen@linux.alibaba.com>
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In-Reply-To: <1700402277-93750-6-git-send-email-guwen@linux.alibaba.com>

On Sun, Nov 19, 2023 at 09:57:55PM +0800, Wen Gu wrote:
> According to virtual ISM support feature defined by SMCv2.1, GIDs of
> virtual ISM device are UUIDs defined by RFC4122, which are 128-bits
> long. So some adaptation work is required. And note that the GIDs of
> existing platform firmware ISM devices still remain 64-bits long.
> 
> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>

...

> diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c

...

> @@ -1522,7 +1527,10 @@ void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid, unsigned short vlan)
>  	/* run common cleanup function and build free list */
>  	spin_lock_bh(&dev->lgr_lock);
>  	list_for_each_entry_safe(lgr, l, &dev->lgr_list, list) {
> -		if ((!peer_gid || lgr->peer_gid == peer_gid) &&
> +		if ((!peer_gid->gid ||

Hi Wen Gu,

Previously this condition assumed that peer could be NULL,
and that is still the case in the next condition, a few lines down.
But with this patch peer is unconditionally dereferenced here.

As flagged by Smatch.

> +		     (lgr->peer_gid.gid == peer_gid->gid &&
> +		      !smc_ism_is_virtual(dev) ? 1 :
> +		      lgr->peer_gid.gid_ext == peer_gid->gid_ext)) &&
>  		    (vlan == VLAN_VID_MASK || lgr->vlan_id == vlan)) {
>  			if (peer_gid) /* peer triggered termination */
>  				lgr->peer_shutdown = 1;

...