OoO En cette matinée pluvieuse du jeudi 23 septembre 2010, vers 10:13, je disais:
I got no answer about this matter. This seems an important drawback since most large MIB will use some symbol from a bogus MIB. RMON2-MIB is one of them. As well as LLDP-MIB. Any hint to debug this situation will be appreciated.
I will try to look again tomorrow at this problem but if someone that knows the code better could take a look...
On Thu, 05 Aug 2010 00:33:35 +0200, Vincent Bernat bernat@luffy.cx wrote:
Hi!
On my computer, smilint RMON2-MIB leads to a segfault because, I think, the rmon symbol is not known because of a missing MIB which leads to an incorrect tokenRing symbol. For example, with smiquery:
MibNode: TOKEN-RING-RMON-MIB::tokenRing OID: 32395664.0 Declaration: <value-assignment> NodeKind: node
I think that the bogus OID is related to the segfault which happens in checkObjects in the loop that should find the parent node which follows an invalid pointer. I have looked around the segfault but every data is corrupted in the core file. Even modulePtr is not correct at all.
I have taken this very small MIB :
INVALID-MIB DEFINITIONS ::= BEGIN
IMPORTS rmon FROM NORFC-MIB;
tokenRing OBJECT IDENTIFIER ::= { rmon 10 }
END
rmon is not solvable and tokenRing is not solvable too. This does not lead to a segfault, but I get bogus OID :
Module: INVALID-MIB MibNode: INVALID-MIB::tokenRing OID: 23465424.0 Declaration: <value-assignment> NodeKind: node
I have followed the parser step by step (smiparse()). At the exit of this function, parser.modulePtr is correct. The first object is rmon with OID 0 and the second object is tokenRing with OID 0.10. However, after freeNodeTree(), the second object OID becomes 0.0. I did not see any other change.
If I comment freeNodeTree() and smiFree() and try again smiquery, I get: Module: INVALID-MIB MibNode: INVALID-MIB::tokenRing OID: 0.10 ParentNode: INVALID-MIB::rmon Declaration: <value-assignment> NodeKind: node
Which seems correct. On the real MIB, I get: Module: RFC1155-SMI Module: TOKEN-RING-RMON-MIB MibNode: TOKEN-RING-RMON-MIB::tokenRing OID: 0.10 ParentNode: TOKEN-RING-RMON-MIB::rmon Declaration: <value-assignment> NodeKind: node
Which is fine too.
However, smilint still segfaults. I have tried to comment other occurrences of the same pattern with no luck. I am not sure to grasp the structures used by the parser but I believe that when there is no way to link a part of the tree, it is freed. Maybe, those nodes should be attached to some fake element in parser-smi.y instead of setting parentPtr to NULL? I have tried to attach them to
modulePtr-> firstObjectPtr without any luck.
Maybe someone can point me in the right direction to get this right?