Re: [PATCH v12 1/4] pstore/blk: new support logger for block devices

From: Dan Carpenter
Date: Tue Mar 05 2019 - 02:13:40 EST


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.

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.

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

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