linux-kernel - [congwang:sch_bpf 2/4] net/core/skb_map.c:175 skb_map_get_next_key() error: we previously assumed 'key' could be null (see line 170)

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Message-ID: <202205221325.tXVMMrOx-lkp@intel.com>
Date:   Mon, 23 May 2022 16:22:15 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     kbuild@...ts.01.org, Cong Wang <xiyou.wangcong@...il.com>
Cc:     lkp@...el.com, kbuild-all@...ts.01.org,
        linux-kernel@...r.kernel.org
Subject: [congwang:sch_bpf 2/4] net/core/skb_map.c:175 skb_map_get_next_key()
 error: we previously assumed 'key' could be null (see line 170)

tree:   https://github.com/congwang/linux.git sch_bpf
head:   6ffa225aaaaa22848f4629fc911a682553f17770
commit: 87784a11f90e7582ee664b531af17f7ca6ce2b62 [2/4] bpf: introduce skb map
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220522/202205221325.tXVMMrOx-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>

smatch warnings:
net/core/skb_map.c:175 skb_map_get_next_key() error: we previously assumed 'key' could be null (see line 170)

vim +/key +175 net/core/skb_map.c

87784a11f90e75 Cong Wang 2020-11-08  164  static int skb_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
87784a11f90e75 Cong Wang 2020-11-08  165  {
87784a11f90e75 Cong Wang 2020-11-08  166  	struct bpf_skb_map *rb = bpf_skb_map(map);
87784a11f90e75 Cong Wang 2020-11-08  167  	struct sk_buff *skb;
87784a11f90e75 Cong Wang 2020-11-08  168  	u64 rank;
87784a11f90e75 Cong Wang 2020-11-08  169  
87784a11f90e75 Cong Wang 2020-11-08 @170  	if (!key) {

If key is NULL

87784a11f90e75 Cong Wang 2020-11-08  171  		skb = skb_rb_first(&rb->root);
87784a11f90e75 Cong Wang 2020-11-08  172  		if (!skb)
87784a11f90e75 Cong Wang 2020-11-08  173  			return -ENOENT;
87784a11f90e75 Cong Wang 2020-11-08  174  	}
87784a11f90e75 Cong Wang 2020-11-08 @175  	rank = *(u64 *) key;

Then we are toasted

87784a11f90e75 Cong Wang 2020-11-08  176  	skb = skb_rb_find(&rb->root, rank);
87784a11f90e75 Cong Wang 2020-11-08  177  	if (!skb)
87784a11f90e75 Cong Wang 2020-11-08  178  		return -ENOENT;
87784a11f90e75 Cong Wang 2020-11-08  179  	skb = skb_rb_next(skb);
87784a11f90e75 Cong Wang 2020-11-08  180  	if (!skb)
87784a11f90e75 Cong Wang 2020-11-08  181  		return 0;
87784a11f90e75 Cong Wang 2020-11-08  182  	*(u64 *) next_key = skb_map_cb(skb)->rank;
87784a11f90e75 Cong Wang 2020-11-08  183  	return 0;
87784a11f90e75 Cong Wang 2020-11-08  184  }

-- 
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