hi Dan Carpenter, On 2019/03/05 15:12, Dan Carpenter wrote: > Hi liaoweixiong, > > url: https://github.com/0day-ci/linux/commits/liaoweixiong/pstore-block-new-support-logger-for-block-devices/20190303-142003 > base: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore > > smatch warnings: > fs/pstore/blkzone.c:180 blkz_zone_write() error: we previously assumed 'zone->buffer' could be null (see line 167) > > # https://github.com/0day-ci/linux/commit/113727d0f1946ad094dbc6531d653a88c7a221bf > git remote add linux-review https://github.com/0day-ci/linux > git remote update linux-review > git checkout 113727d0f1946ad094dbc6531d653a88c7a221bf > vim +180 fs/pstore/blkzone.c > > 113727d0 liaoweixiong 2019-02-28 153 > 113727d0 liaoweixiong 2019-02-28 154 static int blkz_zone_write(struct blkz_zone *zone, > 113727d0 liaoweixiong 2019-02-28 155 enum blkz_flush_mode flush_mode, const char *buf, > 113727d0 liaoweixiong 2019-02-28 156 size_t len, unsigned long off) > 113727d0 liaoweixiong 2019-02-28 157 { > 113727d0 liaoweixiong 2019-02-28 158 struct blkz_info *info = blkz_cxt.bzinfo; > 113727d0 liaoweixiong 2019-02-28 159 ssize_t wcnt; > 113727d0 liaoweixiong 2019-02-28 160 ssize_t (*writeop)(const char *buf, size_t bytes, loff_t pos); > 113727d0 liaoweixiong 2019-02-28 161 size_t wlen; > 113727d0 liaoweixiong 2019-02-28 162 > 113727d0 liaoweixiong 2019-02-28 163 if (off > zone->buffer_size) > 113727d0 liaoweixiong 2019-02-28 164 return -EINVAL; > 113727d0 liaoweixiong 2019-02-28 165 wlen = min_t(size_t, len, zone->buffer_size - off); > 113727d0 liaoweixiong 2019-02-28 166 if (flush_mode != FLUSH_META && flush_mode != FLUSH_NONE) { > 113727d0 liaoweixiong 2019-02-28 @167 if (buf && zone->buffer) > ^^^^^^^^^^^^ > Check. > zone->buffer should not be checked whether null as it will never be null here. I will fix it on next version. zone->buffer was allocated when the zone was initialized (see line 995). Pstore/blk will not go on if allocates buffer for zone->buffer failed. > 113727d0 liaoweixiong 2019-02-28 168 memcpy(zone->buffer->data + off, buf, wlen); > 113727d0 liaoweixiong 2019-02-28 169 atomic_set(&zone->buffer->datalen, wlen + off); > 113727d0 liaoweixiong 2019-02-28 170 } > 113727d0 liaoweixiong 2019-02-28 171 > 113727d0 liaoweixiong 2019-02-28 172 writeop = is_on_panic() ? info->panic_write : info->write; > 113727d0 liaoweixiong 2019-02-28 173 if (!writeop) > 113727d0 liaoweixiong 2019-02-28 174 return -EINVAL; > 113727d0 liaoweixiong 2019-02-28 175 > 113727d0 liaoweixiong 2019-02-28 176 switch (flush_mode) { > 113727d0 liaoweixiong 2019-02-28 177 case FLUSH_NONE: > 113727d0 liaoweixiong 2019-02-28 178 return 0; > 113727d0 liaoweixiong 2019-02-28 179 case FLUSH_PART: > 113727d0 liaoweixiong 2019-02-28 @180 wcnt = writeop((const char *)zone->buffer->data + off, wlen, > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Unchecked. > > 113727d0 liaoweixiong 2019-02-28 181 zone->off + sizeof(*zone->buffer) + off); > ^^^^^^^^^^^^ > This is weird. I can't fetch for-next/pstore so I don't know what > type "buffer" is. It's vague. We also have ->buffer_size which seems > like a more expected way to describe the size. > The type of buffer is struct blkz_buffer (see line 98). struct blkz_buffer is a header of data, who's member data[0] point to real data. The codes "sizeof(*zone->buffer)" just to get size of header. There is a size recorder for blkz_buffer->data on struct blkz_zone. It is no need to write to block device, that's why it do not live in struct blkz_buffer. > 113727d0 liaoweixiong 2019-02-28 182 if (wcnt != wlen) > 113727d0 liaoweixiong 2019-02-28 183 goto set_dirty; > 113727d0 liaoweixiong 2019-02-28 184 case FLUSH_META: > 113727d0 liaoweixiong 2019-02-28 185 wlen = sizeof(struct blkz_buffer); > 113727d0 liaoweixiong 2019-02-28 186 wcnt = writeop((const char *)zone->buffer, wlen, zone->off); > 113727d0 liaoweixiong 2019-02-28 187 if (wcnt != wlen) > 113727d0 liaoweixiong 2019-02-28 188 goto set_dirty; > 113727d0 liaoweixiong 2019-02-28 189 break; > 113727d0 liaoweixiong 2019-02-28 190 case FLUSH_ALL: > 113727d0 liaoweixiong 2019-02-28 191 wlen = buffer_datalen(zone) + sizeof(*zone->buffer); > 113727d0 liaoweixiong 2019-02-28 192 wcnt = writeop((const char *)zone->buffer, wlen, zone->off); > 113727d0 liaoweixiong 2019-02-28 193 if (wcnt != wlen) > 113727d0 liaoweixiong 2019-02-28 194 goto set_dirty; > 113727d0 liaoweixiong 2019-02-28 195 break; > 113727d0 liaoweixiong 2019-02-28 196 } > 113727d0 liaoweixiong 2019-02-28 197 > 113727d0 liaoweixiong 2019-02-28 198 return 0; > 113727d0 liaoweixiong 2019-02-28 199 set_dirty: > 113727d0 liaoweixiong 2019-02-28 200 pr_err("write failed with %zd returned, set dirty\n", wcnt); > 113727d0 liaoweixiong 2019-02-28 201 atomic_set(&zone->dirty, true); > 113727d0 liaoweixiong 2019-02-28 202 return -EBUSY; > 113727d0 liaoweixiong 2019-02-28 203 } > 113727d0 liaoweixiong 2019-02-28 204 > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation > -- liaoweixiong
