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<p class=MsoNormal>We had a customer report that perfquery was crashing on
their nodes when trying to query ports on a switch. When I examined the core
dump, it was clear that libibmad was dereferencing a null pointer from one of
the mad_set_ functions:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#0
0x0000000000000000 in ?? ()<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#1
0x00002ae4e13e7536 in mad_set_field () from /usr/lib64/libibmad.so.5<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#2
0x00002ae4e13e7656 in mad_field_name () from /usr/lib64/libibmad.so.5<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#3
0x0000000000401662 in mad_dump_perfcounters_rcv_sl ()<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#4
0x00000000004024c9 in mad_dump_perfcounters_rcv_sl ()<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#5
0x00002ae4e18168b4 in __libc_start_main () from /lib64/libc.so.6<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#6
0x0000000000401189 in mad_dump_perfcounters_rcv_sl ()<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#7
0x00007fffe5570ce8 in ?? ()<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>#8
0x0000000000000000 in ?? ()<o:p></o:p></span></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>It appears that mad_set_field() was hitting a NULL pointer
in the table of MAD attributes (ib_mad_f). Such entries are being used to separate
different groups of mad attributes in the table.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Reviewing the code, I noted that the mad_set_* and mad_get_*
functions already have some error checking to avoid going completely off the
end of the table, but they do not detect the case where the selected field is
unset. This patch corrects the problem.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Signed Off By: Michael Heinz <michael.heinz@qlogic.com><o:p></o:p></p>
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