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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Divyesh Shah <dpshah@google.com>
Cc: Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org
Subject: question about blkio_get_stat()
Date: Mon, 2 Apr 2012 16:54:56 +0300	[thread overview]
Message-ID: <20120402135455.GA15588@elgon.mountain> (raw)

Hi Divyesh,

Smatch complains that we go outside the array in blkio_get_stat().

block/blk-cgroup.c
   731          if (type == BLKIO_STAT_DEQUEUE)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
BLKIO_STAT_DEQUEUE is 9.

   732                  return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
   733                                          blkg->stats.dequeue, cb, dev);
   734  #endif
   735  
   736          for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
   737                          sub_type++) {
   738                  blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
   739                  cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
                                                    ^^^^^^^^^^^^^^^^^^^^
This array only has 4 elements and if "type" is 9 we're past the end of
array.

   740          }

It's odd that Smatch only started complaining about this now, but this
code has been there for years.  I'm puzzled by what changed.  Sorry if
there is something obvious I have missed.

regards,
dan carpenter

             reply	other threads:[~2012-04-02 13:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-02 13:54 Dan Carpenter [this message]
2012-04-07  8:28 ` question about blkio_get_stat() Jan Kara

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