Hi Loic, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git master head: 8fe088bd4fd12f4c8899b51d5bc3daad98767d49 commit: 89212e160b81e778f829b89743570665810e3b13 [226/269] net: wwan: Fix WWAN config symbols config: i386-allmodconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.3-341-g8af24329-dirty # https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit... git remote add net-next https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git git fetch --no-tags net-next master git checkout 89212e160b81e778f829b89743570665810e3b13 # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) 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(a)intel.com&gt; :::::: CC: David S. Miller <davem(a)davemloft.net&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org