Re: port-alpha/38335 (kernel freeze on alpha MP system)

[Jarle Greipsland <jarle%uninett.no@localhost>]

The following reply was made to PR port-alpha/38335; it has been noted by GNATS.

From: Jarle Greipsland <jarle%uninett.no@localhost>
To: mhitch%lightning.msu.montana.edu@localhost
Cc: gnats-bugs%NetBSD.org@localhost, gnats-admin%netbsd.org@localhost
Subject: Re: port-alpha/38335 (kernel freeze on alpha MP system)
Date: Tue, 06 Oct 2009 11:17:09 +0200 (CEST)

 "Michael L. Hitch" <mhitch%lightning.msu.montana.edu@localhost> writes:
 >    One thing I haven't tried yet is a LOCKDEBUG kernel, which should do 
 > some additional checking on locking, and should be able to provide 
 > information on what holds the lock.  This last time I tried LOCKDEBUG, I 
 > ran into problems and quickly got lost in the locking morass.
 Some time ago I tried to boot a LOCKDEBUG kernel, but it paniced
 during autoconfig with an assertion:
 Mutex error: lockdebug_alloc: already initialized
 This is registered as port-alpha/38358
 
 > >>    This is the problem I'm still in the process of trying to figure out
 > >> what the problem is and how to fix it.  The patch I posted previously is a
 > >> workaround to detect this particular problem, and will display a message
 > >> if it occurs.
 > > It _does_ occur.  I applied the patch, and a 'build.sh -j4'
 > > triggered the panic after a while.
 > 
 >    What was the panic you got?
 The one from your patch:
 Whoa!  pool_cache_get returned an in-use entry! ci_index 0 pj 
0xfffffc003f9ee740
 panic: Oops
 Stopped in pid 9356.1 (as) at   netbsd:cpu_Debugger+0x4:        ret     
zero,(ra)
 db{0}> trace
 cpu_Debugger() at netbsd:cpu_Debugger+0x4
 panic() at netbsd:panic+0x268
 pmap_tlb_shootdown() at netbsd:pmap_tlb_shootdown+0x274
 pmap_kenter_pa() at netbsd:pmap_kenter_pa+0xe8
 uvm_pagermapin() at netbsd:uvm_pagermapin+0x1b4
 genfs_gop_write() at netbsd:genfs_gop_write+0x48
 genfs_do_putpages() at netbsd:genfs_do_putpages+0x74c
 VOP_PUTPAGES() at netbsd:VOP_PUTPAGES+0xb0
 ffs_write() at netbsd:ffs_write+0x728
 VOP_WRITE() at netbsd:VOP_WRITE+0xb0
 vn_write() at netbsd:vn_write+0x10c
 dofilewrite() at netbsd:dofilewrite+0x90
 sys_write() at netbsd:sys_write+0xa8
 syscall_plain() at netbsd:syscall_plain+0x160
 XentSys() at netbsd:XentSys+0x60
 --- syscall (4) ---
 --- user mode ---
 
                                        -jarle