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

kernel test robot
2021-12-04T19:24:06Z

head: bbef3c7a63d2a4cb0f3f839db9e767f168c5e348
commit: f7af616c632ee2ac3af0876fe33bf9e0232e665a net: iosm: infrastructure
date: 6 months ago
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20211205/202112050318.uBUvlyTo-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-dirty
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f7af616c632ee2ac3af0876fe33bf9e0232e665a
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout f7af616c632ee2ac3af0876fe33bf9e0232e665a
# save the config file to linux build tree
mkdir build_dir
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/net/wwan/iosm/ drivers/staging/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

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@intel.com>
:::::: CC: David S. Miller <davem@davemloft.net>

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0-DAY CI Kernel Test Service, Intel Corporation