Re: kern/52252: uvm_km_check_empty panic when loading any module

[Jaromír Doleček <jaromir.dolecek%gmail.com@localhost>]

The following reply was made to PR kern/52252; it has been noted by GNATS.

From: =?UTF-8?B?SmFyb23DrXIgRG9sZcSNZWs=?= <jaromir.dolecek%gmail.com@localhost>
To: Anthony Mallet <tho%netbsd.org@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, 
	netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/52252: uvm_km_check_empty panic when loading any module
Date: Tue, 23 May 2017 23:04:16 +0200

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 Hello,
 
 usually two things to check for wierd panic cases like this.
 
 1. make sure to rebuild your complete kernel, to make sure no obsolete .o
 were used - make clean && make depend && make
 2. make sure that DEBUG/LOCKDEBUG options between your kernel and the
 modules match - since DEBUG and LOCKDEBUG change size of critical kernel
 structures, kernel will trample over random structure contents since what
 module allocates is less than the kernel uses.
 
 Looking on your config, it seems you do have the DEBUG and LOCKDEBUG
 options there, so I think that is your problem.
 
 Jaromir
 
 
 2017-05-23 22:29 GMT+02:00 Anthony Mallet <tho%netbsd.org@localhost>:
 
 > >  3. Can you reproduce this problem using a GENERIC kernel on the real
 > >      machine?
 >
 > It seems to be OK with GENERIC. At least I can load modules with no
 > issue on one of the machine (did not try the other one yet). So that's
 > a strong hint.
 >
 > I had already compared my config with GENERIC without noticing
 > anything suspect, but maybe you'll spot something.
 >
 >
 > # Diagnostic/debugging support options
 > makeoptions     COPTS="-O2 -fno-omit-frame-pointer"
 > #options        DIAGNOSTIC      # expensive kernel consistency checks
 >                                 # XXX to be commented out on release branch
 > options         DEBUG           # expensive debugging checks/support
 > options         LOCKDEBUG       # expensive locking checks/support
 > #options        KMEMSTATS       # kernel memory statistics (vmstat -m)
 > makeoptions     DEBUG="-g"      # compile full symbol table
 >
 >
 
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 <div dir=3D"ltr"><div>Hello,</div><div><br></div><div>usually two things to=
  check for wierd panic cases like this.</div><div><br></div><div>1. make su=
 re to rebuild your complete kernel, to make sure no obsolete .o were used -=
  make clean &amp;&amp; make depend &amp;&amp; make</div><div>2. make sure t=
 hat DEBUG/LOCKDEBUG options between your kernel and the modules match - sin=
 ce DEBUG and LOCKDEBUG change size of critical kernel structures, kernel wi=
 ll trample over random structure contents since what module allocates is le=
 ss than the kernel uses.</div><div><br></div><div>Looking on your config, i=
 t seems you do have the DEBUG and LOCKDEBUG options there, so I think that =
 is your problem.</div><div><br></div><div>Jaromir</div><br><div class=3D"gm=
 ail_extra"><br><div class=3D"gmail_quote">2017-05-23 22:29 GMT+02:00 Anthon=
 y Mallet <span dir=3D"ltr">&lt;<a href=3D"mailto:tho%netbsd.org@localhost"; target=3D"=
 _blank">tho%netbsd.org@localhost</a>&gt;</span>:<br><blockquote class=3D"gmail_quote"=
  style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><s=
 pan class=3D"">&gt;=C2=A0 3. Can you reproduce this problem using a GENERIC=
  kernel on the real<br>
 &gt;=C2=A0 =C2=A0 =C2=A0 machine?<br>
 <br>
 </span>It seems to be OK with GENERIC. At least I can load modules with no<=
 br>
 issue on one of the machine (did not try the other one yet). So that&#39;s<=
 br>
 a strong hint.<br>
 <br>
 I had already compared my config with GENERIC without noticing<br>
 anything suspect, but maybe you&#39;ll spot something.<br><br><br>
 # Diagnostic/debugging support options<br>
 makeoptions=C2=A0 =C2=A0 =C2=A0COPTS=3D&quot;-O2 -fno-omit-frame-pointer&qu=
 ot;<br>
 #options=C2=A0 =C2=A0 =C2=A0 =C2=A0 DIAGNOSTIC=C2=A0 =C2=A0 =C2=A0 # expens=
 ive kernel consistency checks<br>
 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
 =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 # XXX to be commented out on release=
  branch<br>
 options=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0DEBUG=C2=A0 =C2=A0 =C2=A0 =C2=A0 =
 =C2=A0 =C2=A0# expensive debugging checks/support<br>
 options=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0LOCKDEBUG=C2=A0 =C2=A0 =C2=A0 =C2=
 =A0# expensive locking checks/support<br>
 #options=C2=A0 =C2=A0 =C2=A0 =C2=A0 KMEMSTATS=C2=A0 =C2=A0 =C2=A0 =C2=A0# k=
 ernel memory statistics (vmstat -m)<br>
 <span class=3D"">makeoptions=C2=A0 =C2=A0 =C2=A0DEBUG=3D&quot;-g&quot;=C2=
 =A0 =C2=A0 =C2=A0 # compile full symbol table<br>
 <br></span></blockquote></div></div></div>
 
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