drivers/net/wwan/iosm/iosm_ipc_mux_codec.c:833:21: sparse: sparse: Using plain integer as NULL pointer

[kernel test robot]

Hi Loic,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   d0e60d46bc03252b8d4ffaaaa0b371970ac16cda
commit: 89212e160b81e778f829b89743570665810e3b13 net: wwan: Fix WWAN config symbols
date:   12 months ago
config: i386-allmodconfig (https://download.01.org/0day-ci/archive/20220605/202206051123.UxnYthu7-lkp@xxxxxxxxx/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-18-g56afb504-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=89212e160b81e778f829b89743570665810e3b13
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 89212e160b81e778f829b89743570665810e3b13
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/ samples//

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>


sparse warnings: (new ones prefixed by >>)
>> drivers/net/wwan/iosm/iosm_ipc_mux_codec.c:833:21: sparse: sparse: Using plain integer as NULL pointer

vim +833 drivers/net/wwan/iosm/iosm_ipc_mux_codec.c

9413491e20e1ab M Chetan Kumar 2021-06-13  814  
9413491e20e1ab M Chetan Kumar 2021-06-13  815  void ipc_mux_ul_encoded_process(struct iosm_mux *ipc_mux, struct sk_buff *skb)
9413491e20e1ab M Chetan Kumar 2021-06-13  816  {
9413491e20e1ab M Chetan Kumar 2021-06-13  817  	struct mux_adgh *adgh;
9413491e20e1ab M Chetan Kumar 2021-06-13  818  	u16 adgh_len;
9413491e20e1ab M Chetan Kumar 2021-06-13  819  
9413491e20e1ab M Chetan Kumar 2021-06-13  820  	adgh = (struct mux_adgh *)skb->data;
9413491e20e1ab M Chetan Kumar 2021-06-13  821  	adgh_len = le16_to_cpu(adgh->length);
9413491e20e1ab M Chetan Kumar 2021-06-13  822  
9413491e20e1ab M Chetan Kumar 2021-06-13  823  	if (adgh->signature == cpu_to_le32(MUX_SIG_ADGH) &&
9413491e20e1ab M Chetan Kumar 2021-06-13  824  	    ipc_mux->ul_flow == MUX_UL)
9413491e20e1ab M Chetan Kumar 2021-06-13  825  		ipc_mux->ul_data_pend_bytes = ipc_mux->ul_data_pend_bytes -
9413491e20e1ab M Chetan Kumar 2021-06-13  826  					      adgh_len;
9413491e20e1ab M Chetan Kumar 2021-06-13  827  
9413491e20e1ab M Chetan Kumar 2021-06-13  828  	if (ipc_mux->ul_flow == MUX_UL)
9413491e20e1ab M Chetan Kumar 2021-06-13  829  		dev_dbg(ipc_mux->dev, "ul_data_pend_bytes: %lld",
9413491e20e1ab M Chetan Kumar 2021-06-13  830  			ipc_mux->ul_data_pend_bytes);
9413491e20e1ab M Chetan Kumar 2021-06-13  831  
9413491e20e1ab M Chetan Kumar 2021-06-13  832  	/* Reset the skb settings. */
9413491e20e1ab M Chetan Kumar 2021-06-13 @833  	skb->tail = 0;
9413491e20e1ab M Chetan Kumar 2021-06-13  834  	skb->len = 0;
9413491e20e1ab M Chetan Kumar 2021-06-13  835  
9413491e20e1ab M Chetan Kumar 2021-06-13  836  	/* Add the consumed ADB to the free list. */
9413491e20e1ab M Chetan Kumar 2021-06-13  837  	skb_queue_tail((&ipc_mux->ul_adb.free_list), skb);
9413491e20e1ab M Chetan Kumar 2021-06-13  838  }
9413491e20e1ab M Chetan Kumar 2021-06-13  839  

:::::: The code at line 833 was first introduced by commit
:::::: 9413491e20e1aba6e471d90c19cc43e523216a4d net: iosm: encode or decode datagram

:::::: TO: M Chetan Kumar <m.chetan.kumar@xxxxxxxxx>
:::::: CC: David S. Miller <davem@xxxxxxxxxxxxx>

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