Re: install/50357: warning message from anita

[Paul Goyette <paul%whooppee.com@localhost>]

The following reply was made to PR install/50357; it has been noted by GNATS.

From: Paul Goyette <paul%whooppee.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: install/50357: warning message from anita
Date: Fri, 10 Jun 2016 08:41:49 +0800 (PHT)

 (I've updated the synopsis for this PR to reflect the real problem.)
 
 So, here's what's happening...
 
 1. Various routines in lib/libsa code set the global variable 'fsmod'
     to identify the root file-system.  This appears to be done for
     msdosfs, nfs, ext2fs, cd9660, and ffs file-systems.
 
 2. In arch/i386/stand/lib/libexec.c the 'fsmod' variable is checked.
     If it is non-NULL, the named module is added to the list of modules
     that gets "passed in" to the kernel.
 
 3. Early in kernel initialization, we call module_init(), which calls
     module_init_md().  At least on i386 and amd64, this calls
     module_prime() which tries to load the specified module, including
     symbol resolution.
 
 The problem is, there's no check being made to see if the fs module is
 already built-in to the kernel.  The symbol relocation fails because 
 they're all already defined, so the module load fails.
 
 This used to be a fairly minor issue, but with the recent commit of a 
 fix for kern/45125 we're now reporting each attempt to redefine the 
 symbols, so lots of messages!
 
 This problem appears in the installation CD-ROM image when booted.  On 
 the automated test runs on babylon5 it seems that the target (installed) 
 system is not affected.  However, there is at least one user who has 
 (in private E-mail) reported this problem occurring in a recently 
 updated running system.
 
 Thanks to gson@ for providing the time-range for when this problem may 
 have been introduced.  However, looking through the list of commits he 
 provided doesn't offer any clues.
 
 
 
 +------------------+--------------------------+------------------------+
 | Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:      |
 | (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com   |
 | Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org |
 +------------------+--------------------------+------------------------+