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 <[email protected]>
Reported-by: Dan Carpenter <[email protected]>

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/?id=c80ed84e76886487703bf04b38ce10e92e2d6e26
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/[email protected]

Attachment: .config.gz
Description: application/gzip

Reply via email to