CC: [email protected]
CC: [email protected]
TO: Coly Li <[email protected]>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/colyli/linux-bcache.git 
nvdimm-meta
head:   a12f8ec824edd1317f14882c7d0aee5e5c941edd
commit: 5f408d113974d2bb3eb1b237d549724f7509ab23 [11/12] bcache: read jset from 
NVDIMM pages for journal replay
:::::: branch date: 8 hours ago
:::::: commit date: 8 hours ago
config: x86_64-randconfig-m001-20210804 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>

smatch warnings:
drivers/md/bcache/journal.c:114 journal_read_bucket() error: potentially 
dereferencing uninitialized 'j'.

vim +/j +114 drivers/md/bcache/journal.c

cafe563591446c Kent Overstreet   2013-03-23  106  
cafe563591446c Kent Overstreet   2013-03-23  107                /* This 
function could be simpler now since we no longer write
cafe563591446c Kent Overstreet   2013-03-23  108                 * journal 
entries that overlap bucket boundaries; this means
cafe563591446c Kent Overstreet   2013-03-23  109                 * the start of 
a bucket will always have a valid journal entry
cafe563591446c Kent Overstreet   2013-03-23  110                 * if it has 
any journal entries at all.
cafe563591446c Kent Overstreet   2013-03-23  111                 */
cafe563591446c Kent Overstreet   2013-03-23  112                while (len) {
cafe563591446c Kent Overstreet   2013-03-23  113                        struct 
list_head *where;
cafe563591446c Kent Overstreet   2013-03-23 @114                        size_t 
blocks, bytes = set_bytes(j);
cafe563591446c Kent Overstreet   2013-03-23  115  
b3fa7e77e67e64 Kent Overstreet   2013-08-05  116                        if 
(j->magic != jset_magic(&ca->sb)) {
46f5aa8806e34f Joe Perches       2020-05-27  117                                
pr_debug("%u: bad magic\n", bucket_index);
cafe563591446c Kent Overstreet   2013-03-23  118                                
return ret;
b3fa7e77e67e64 Kent Overstreet   2013-08-05  119                        }
cafe563591446c Kent Overstreet   2013-03-23  120  
b3fa7e77e67e64 Kent Overstreet   2013-08-05  121                        if 
(bytes > left << 9 ||
b3fa7e77e67e64 Kent Overstreet   2013-08-05  122                            
bytes > PAGE_SIZE << JSET_BITS) {
46f5aa8806e34f Joe Perches       2020-05-27  123                                
pr_info("%u: too big, %zu bytes, offset %u\n",
b3fa7e77e67e64 Kent Overstreet   2013-08-05  124                                
        bucket_index, bytes, offset);
cafe563591446c Kent Overstreet   2013-03-23  125                                
return ret;
b3fa7e77e67e64 Kent Overstreet   2013-08-05  126                        }
cafe563591446c Kent Overstreet   2013-03-23  127  
cafe563591446c Kent Overstreet   2013-03-23  128                        if 
(bytes > len << 9)
cafe563591446c Kent Overstreet   2013-03-23  129                                
goto reread;
cafe563591446c Kent Overstreet   2013-03-23  130  
b3fa7e77e67e64 Kent Overstreet   2013-08-05  131                        if 
(j->csum != csum_set(j)) {
46f5aa8806e34f Joe Perches       2020-05-27  132                                
pr_info("%u: bad csum, %zu bytes, offset %u\n",
b3fa7e77e67e64 Kent Overstreet   2013-08-05  133                                
        bucket_index, bytes, offset);
cafe563591446c Kent Overstreet   2013-03-23  134                                
return ret;
b3fa7e77e67e64 Kent Overstreet   2013-08-05  135                        }
cafe563591446c Kent Overstreet   2013-03-23  136  
4e1ebae3ee4e0c Coly Li           2020-10-01  137                        blocks 
= set_blocks(j, block_bytes(ca));
cafe563591446c Kent Overstreet   2013-03-23  138  
2464b693148e5d Coly Li           2019-06-28  139                        /*
2464b693148e5d Coly Li           2019-06-28  140                         * 
Nodes in 'list' are in linear increasing order of
2464b693148e5d Coly Li           2019-06-28  141                         * 
i->j.seq, the node on head has the smallest (oldest)
2464b693148e5d Coly Li           2019-06-28  142                         * 
journal seq, the node on tail has the biggest
2464b693148e5d Coly Li           2019-06-28  143                         * 
(latest) journal seq.
2464b693148e5d Coly Li           2019-06-28  144                         */
2464b693148e5d Coly Li           2019-06-28  145  
2464b693148e5d Coly Li           2019-06-28  146                        /*
2464b693148e5d Coly Li           2019-06-28  147                         * 
Check from the oldest jset for last_seq. If
2464b693148e5d Coly Li           2019-06-28  148                         * 
i->j.seq < j->last_seq, it means the oldest jset
2464b693148e5d Coly Li           2019-06-28  149                         * in 
list is expired and useless, remove it from
9c9b81c45619e7 Bhaskar Chowdhury 2021-04-11  150                         * this 
list. Otherwise, j is a candidate jset for
2464b693148e5d Coly Li           2019-06-28  151                         * 
further following checks.
2464b693148e5d Coly Li           2019-06-28  152                         */
cafe563591446c Kent Overstreet   2013-03-23  153                        while 
(!list_empty(list)) {
cafe563591446c Kent Overstreet   2013-03-23  154                                
i = list_first_entry(list,
cafe563591446c Kent Overstreet   2013-03-23  155                                
        struct journal_replay, list);
cafe563591446c Kent Overstreet   2013-03-23  156                                
if (i->j.seq >= j->last_seq)
cafe563591446c Kent Overstreet   2013-03-23  157                                
        break;
cafe563591446c Kent Overstreet   2013-03-23  158                                
list_del(&i->list);
cafe563591446c Kent Overstreet   2013-03-23  159                                
kfree(i);
cafe563591446c Kent Overstreet   2013-03-23  160                        }
cafe563591446c Kent Overstreet   2013-03-23  161  
2464b693148e5d Coly Li           2019-06-28  162                        /* 
iterate list in reverse order (from latest jset) */
cafe563591446c Kent Overstreet   2013-03-23  163                        
list_for_each_entry_reverse(i, list, list) {
cafe563591446c Kent Overstreet   2013-03-23  164                                
if (j->seq == i->j.seq)
cafe563591446c Kent Overstreet   2013-03-23  165                                
        goto next_set;
cafe563591446c Kent Overstreet   2013-03-23  166  
2464b693148e5d Coly Li           2019-06-28  167                                
/*
2464b693148e5d Coly Li           2019-06-28  168                                
 * if j->seq is less than any i->j.last_seq
2464b693148e5d Coly Li           2019-06-28  169                                
 * in list, j is an expired and useless jset.
2464b693148e5d Coly Li           2019-06-28  170                                
 */
cafe563591446c Kent Overstreet   2013-03-23  171                                
if (j->seq < i->j.last_seq)
cafe563591446c Kent Overstreet   2013-03-23  172                                
        goto next_set;
cafe563591446c Kent Overstreet   2013-03-23  173  
2464b693148e5d Coly Li           2019-06-28  174                                
/*
2464b693148e5d Coly Li           2019-06-28  175                                
 * 'where' points to first jset in list which
2464b693148e5d Coly Li           2019-06-28  176                                
 * is elder then j.
2464b693148e5d Coly Li           2019-06-28  177                                
 */
cafe563591446c Kent Overstreet   2013-03-23  178                                
if (j->seq > i->j.seq) {
cafe563591446c Kent Overstreet   2013-03-23  179                                
        where = &i->list;
cafe563591446c Kent Overstreet   2013-03-23  180                                
        goto add;
cafe563591446c Kent Overstreet   2013-03-23  181                                
}
cafe563591446c Kent Overstreet   2013-03-23  182                        }
cafe563591446c Kent Overstreet   2013-03-23  183  
cafe563591446c Kent Overstreet   2013-03-23  184                        where = 
list;
cafe563591446c Kent Overstreet   2013-03-23  185  add:
cafe563591446c Kent Overstreet   2013-03-23  186                        i = 
kmalloc(offsetof(struct journal_replay, j) +
cafe563591446c Kent Overstreet   2013-03-23  187                                
    bytes, GFP_KERNEL);
cafe563591446c Kent Overstreet   2013-03-23  188                        if (!i)
cafe563591446c Kent Overstreet   2013-03-23  189                                
return -ENOMEM;
cafe563591446c Kent Overstreet   2013-03-23  190                        
memcpy(&i->j, j, bytes);
2464b693148e5d Coly Li           2019-06-28  191                        /* Add 
to the location after 'where' points to */
cafe563591446c Kent Overstreet   2013-03-23  192                        
list_add(&i->list, where);
cafe563591446c Kent Overstreet   2013-03-23  193                        ret = 1;
cafe563591446c Kent Overstreet   2013-03-23  194  
a231f07a5fe30a Coly Li           2019-06-28  195                        if 
(j->seq > ja->seq[bucket_index])
cafe563591446c Kent Overstreet   2013-03-23  196                                
ja->seq[bucket_index] = j->seq;
cafe563591446c Kent Overstreet   2013-03-23  197  next_set:
cafe563591446c Kent Overstreet   2013-03-23  198                        offset  
+= blocks * ca->sb.block_size;
cafe563591446c Kent Overstreet   2013-03-23  199                        len     
-= blocks * ca->sb.block_size;
cafe563591446c Kent Overstreet   2013-03-23  200                        j = 
((void *) j) + blocks * block_bytes(ca);
cafe563591446c Kent Overstreet   2013-03-23  201                }
cafe563591446c Kent Overstreet   2013-03-23  202        }
cafe563591446c Kent Overstreet   2013-03-23  203  
cafe563591446c Kent Overstreet   2013-03-23  204        return ret;
cafe563591446c Kent Overstreet   2013-03-23  205  }
cafe563591446c Kent Overstreet   2013-03-23  206  

:::::: The code at line 114 was first introduced by commit
:::::: cafe563591446cf80bfbc2fe3bc72a2e36cf1060 bcache: A block layer cache

:::::: TO: Kent Overstreet <[email protected]>
:::::: CC: Kent Overstreet <[email protected]>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]

Attachment: .config.gz
Description: application/gzip

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