why does ipcs command shows many undetached shared memory with key 0x0000000?
<p>I discover many undetached shared memory with key 0x0000000 with <code>ipcs</code> like these:</p>

<pre><code>0x00000000 585728074  nobody     777        48         0                       
0x00000000 585760843  nobody     777        48         0                       
0x00000000 586711116  nobody     777        48         0                       
0x00000000 586743885  nobody     777        48         0                       
0x00000000 587104334  nobody     777        48         0                       
0x00000000 587137103  nobody     777        48         0                       
0x00000000 587694160  nobody     777        48         0                       
0x00000000 587726929  nobody     777        48         0                       
0x00000000 588087378  nobody     777        48         0                       
0x00000000 588120147  nobody     777        48         0                       
0x00000000 588480596  nobody     777        48         0                       
0x00000000 588513365  nobody     777        48         0                       
0x00000000 588742742  nobody     777        48         0                       
0x00000000 588775511  nobody     777        48         0                       
0x00000000 588939352  nobody     777        48         0                       
0x00000000 588972121  nobody     777        48         0                       
0x00000000 589135962  nobody     777        48         0                       
0x00000000 589168731  nobody     777        48         0                       
0x00000000 589791324  nobody     777        48         0                       
0x00000000 589824093  nobody     777        48         0                       
0x00000000 589987934  nobody     777        48         0                       
</code></pre>

<p>It is quite strange because the value of <code>nattach</code> parameters are all 0, which means no process is attaching to them and they should be deleted in this case.</p>

<p>What am I missing? I don't know which process causes this. Is there any way to find out?</p>