tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 9cb1fd0efd195590b828b9b865421ad345a4a145 commit: c80ed84e76886487703bf04b38ce10e92e2d6e26 net: dsa: tag_8021q: Fix dsa_8021q_restore_pvid for an absent pvid date: 6 months ago config: x86_64-randconfig-m001-20200526 (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; smatch warnings: net/dsa/tag_8021q.c:109 dsa_8021q_restore_pvid() error: uninitialized symbol 'pvid'. # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git remote update linus git checkout c80ed84e76886487703bf04b38ce10e92e2d6e26 vim +/pvid +109 net/dsa/tag_8021q.c 5f33183b7fdfeb Vladimir Oltean 2019-08-30 96 static int dsa_8021q_restore_pvid(struct dsa_switch *ds, int port) 5f33183b7fdfeb Vladimir Oltean 2019-08-30 97 { 5f33183b7fdfeb Vladimir Oltean 2019-08-30 98 struct bridge_vlan_info vinfo; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 99 struct net_device *slave; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 100 u16 pvid; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 101 int err; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 102 5f33183b7fdfeb Vladimir Oltean 2019-08-30 103 if (!dsa_is_user_port(ds, port)) 5f33183b7fdfeb Vladimir Oltean 2019-08-30 104 return 0; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 105 5f33183b7fdfeb Vladimir Oltean 2019-08-30 106 slave = ds->ports[port].slave; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 107 5f33183b7fdfeb Vladimir Oltean 2019-08-30 108 err = br_vlan_get_pvid(slave, &pvid); c80ed84e768864 Vladimir Oltean 2019-11-16 @109 if (!pvid || err < 0) ^^^^^^^^^^^^^^^^ I don't know why this warning is only showing up now in May 2020... Anyway, we could solve the problem by checking for errors first: if (err < 0 || !pvid) { The UBSan tool can detect uninitialized values used at runtime so it might generate a splat as well. Other than that, obviously it is harmless. 5f33183b7fdfeb Vladimir Oltean 2019-08-30 110 /* There is no pvid on the bridge for this port, which is 5f33183b7fdfeb Vladimir Oltean 2019-08-30 111 * perfectly valid. Nothing to restore, bye-bye! 5f33183b7fdfeb Vladimir Oltean 2019-08-30 112 */ 5f33183b7fdfeb Vladimir Oltean 2019-08-30 113 return 0; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 114 5f33183b7fdfeb Vladimir Oltean 2019-08-30 115 err = br_vlan_get_info(slave, pvid, &vinfo); 5f33183b7fdfeb Vladimir Oltean 2019-08-30 116 if (err < 0) { 5f33183b7fdfeb Vladimir Oltean 2019-08-30 117 dev_err(ds->dev, "Couldn't determine PVID attributes\n"); 5f33183b7fdfeb Vladimir Oltean 2019-08-30 118 return err; 5f33183b7fdfeb Vladimir Oltean 2019-08-30 119 } 5f33183b7fdfeb Vladimir Oltean 2019-08-30 120 5f33183b7fdfeb Vladimir Oltean 2019-08-30 121 return dsa_port_vid_add(&ds->ports[port], pvid, vinfo.flags); 5f33183b7fdfeb Vladimir Oltean 2019-08-30 122 } --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org