kern/186362: [panic] _mtx_lock_sleep() misses check for NULL

[Andriy Gapon]

The following reply was made to PR kern/186362; it has been noted by GNATS.

From: Andriy Gapon <avg at FreeBSD.org>
To: bug-followup at FreeBSD.org, eugen at grosbein.net
Cc:  
Subject: Re: kern/186362: [panic] _mtx_lock_sleep() misses check for NULL
Date: Sun, 02 Feb 2014 14:55:28 +0200

 NULL check would be redundant there as it is already established that the lock
 is owned and thus must have an owner.
 What seems to be happening that is that the thread is trying to acquire a lock
 that has been corrupted somehow.  E.g. never initialized or its memory location
 overwritten.
 
 Better diagnostics for that case when INVARIANTS are enabled is warranted though.
 
 Returning to the main issue, I wonder if the following message are related to
 the problem:
 
 module_register: module mac_portacl already exists!
 Module mac_portacl failed to register: 17
 
 I seem to recall that in some cases our kernel module loading infrastructure may
 refuse to load a duplicate module, bu nevertheless re-resolve a symbol name to
 point to a symbol in the duplicate module rather than in the original.  Which is
 a bug, of course.
 
 -- 
 Andriy Gapon