[OpenAFS-devel] AIX debugging help - kernel panic with Open XL C 17.1.0

Ben Huntsman ben@huntsmans.net
Mon, 20 Oct 2025 16:23:25 +0000 

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Hi everyone-
   I could use a little help with this if anyone knows even a little about =
CLANG, and also knows this code better than I do.  I'm still working on get=
ting the kernel extension to work under AIX when compiled using the new CLA=
NG-based Open XL C 17.1.0.  I have put together a few patches which allow i=
t compile successfully and load into the kernel without causing a panic.  M=
y changes are on my private branch here:

https://github.com/bhuntsman/openafs/tree/xlc-17.1.0-support

   Loading of the modules is successful, and once it is, bosserver runs fin=
e.  But as soon as I try to start afsd, I get the following kernel panic:

VSX Unavailable
.afs_UpdateCellLRU+000074           xxlxor    vsr0,vsr0,vsr0
KDB(1)> where
pvthread+097F00 STACK:
[F10009D5B06C22C4]afs_UpdateCellLRU+000074 (00000000017F013F)
[F10009D5B06C21C0]afs_GetCellByName+000080 (0000000000000000, F10009D5B096F=
390)
[F10009D5B06D0680]afs_InitDynroot+00008C ()
[F10009D5B074F274]afs_syscall_call+000F18 (0000000000000000, 00000000200247=
58,
   F00000002FF47170, 2800223400000000, 000000000079D570, 3B302355DEADBEEF)
[F10009D5B074DEFC]syscall+0000C8 (000000002009C3E8, 000000002009C408,
   000000002009C528, 0000000000000000, 0000000000000000, 0000000000000000,
   0000000000000000)
[00014D70].hkey_legacy_gate+00004C ()
[00003984]syscall+000244 ()
[kdb_get_virtual_doubleword] no real storage @ FFFFFFFF3FFFE70

KDB(1)>

   This looks like it's in src/afs/afs_cell.c.  Not entirely sure what's go=
ing on here but looks like some null pointer problems possibly?  This code =
works fine when compiled using XL C 16.1, even with the changes in my priva=
te branch linked above.  Is there perhaps a CLANG option someone is aware o=
f that might be of use?

   Any pointers (haha) would be greatly appreciated!

-Ben



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s=3D"elementToProof">
Hi everyone-</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
&nbsp; &nbsp;I could use a little help with this if anyone knows even a lit=
tle about CLANG, and also knows this code better than I do.&nbsp; I'm still=
 working on getting the kernel extension to work under AIX when compiled us=
ing the new CLANG-based Open XL C 17.1.0.&nbsp; I have
 put together a few patches which allow it compile successfully and load in=
to the kernel without causing a panic.&nbsp; My changes are on my private b=
ranch here:</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
<br>
</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
<a class=3D"OWAAutoLink" id=3D"OWAb369c036-e1d3-1faf-f9f5-bdc6e0a1c025" hre=
f=3D"https://github.com/bhuntsman/openafs/tree/xlc-17.1.0-support">https://=
github.com/bhuntsman/openafs/tree/xlc-17.1.0-support</a></div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
<br>
</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
&nbsp; &nbsp;Loading of the modules is successful, and once it is, bosserve=
r runs fine.&nbsp; But as soon as I try to start afsd, I get the following =
kernel panic:</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
<br>
</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
VSX Unavailable</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
.afs_UpdateCellLRU+000074 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; xxlxor&nbsp; &=
nbsp; vsr0,vsr0,vsr0</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
KDB(1)&gt; where</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
pvthread+097F00 STACK:</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[F10009D5B06C22C4]afs_UpdateCellLRU+000074 (00000000017F013F)</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[F10009D5B06C21C0]afs_GetCellByName+000080 (0000000000000000, F10009D5B096F=
390)</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[F10009D5B06D0680]afs_InitDynroot+00008C ()</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[F10009D5B074F274]afs_syscall_call+000F18 (0000000000000000, 00000000200247=
58,</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
&nbsp;&nbsp; F00000002FF47170, 2800223400000000, 000000000079D570, 3B302355=
DEADBEEF)</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[F10009D5B074DEFC]syscall+0000C8 (000000002009C3E8, 000000002009C408,</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
&nbsp;&nbsp; 000000002009C528, 0000000000000000, 0000000000000000, 00000000=
00000000,</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
&nbsp;&nbsp; 0000000000000000)</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[00014D70].hkey_legacy_gate+00004C ()</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[00003984]syscall+000244 ()</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
[kdb_get_virtual_doubleword] no real storage @ FFFFFFFF3FFFE70</div>
<div style=3D"line-height: normal; margin: 0px; min-height: 13px; font-fami=
ly: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, san=
s-serif; font-size: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
<br>
</div>
<div style=3D"line-height: normal; margin: 0px; font-family: Aptos, Aptos_E=
mbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size=
: 12pt; color: rgb(0, 0, 0);" class=3D"elementToProof">
KDB(1)&gt;&nbsp;</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
<br>
</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
&nbsp; &nbsp;This looks like it's in src/afs/afs_cell.c.&nbsp; Not entirely=
 sure what's going on here but looks like some null pointer problems possib=
ly?&nbsp; This code works fine when compiled using XL C 16.1, even with the=
 changes in my private branch linked above.&nbsp; Is there
 perhaps a CLANG option someone is aware of that might be of use?</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
<br>
</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
&nbsp; &nbsp;Any pointers (haha) would be greatly appreciated!<br>
<br>
</div>
<div style=3D"font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, =
Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" clas=
s=3D"elementToProof">
-Ben</div>
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<br>
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