panic on yesterday's -CURRENT: linux emulation and vm (lockmgr: locking against myself)

[Adam Migus]

Alan Cox wrote:

>On Thu, Sep 25, 2003 at 11:15:57AM -0400, Robert Watson wrote:
>  
>
>>...
>>#6  0xc049f355 in vm_fault (map=0xc6fc1700, vaddr=0, fault_type=1 '\001', 
>>    fault_flags=0) at /usr/src/sys/vm/vm_fault.c:219
>>#7  0xc04eddd9 in trap_pfault (frame=0xdd699b18, usermode=0, eva=0)
>>    at /usr/src/sys/i386/i386/trap.c:709
>>#8  0xc04eda50 in trap (frame=
>>      {tf_fs = -1070333928, tf_es = -1067384816, tf_ds = 16, tf_edi = 0,
>>tf_esi = -1068054086, tf_ebp = -580281484, tf_isp = -580281532, tf_ebx =
>>441, tf_edx = -968258896, tf_ecx = 0, tf_eax = -968258896, tf_trapno = 12,
>>tf_err = 0, tf_eip = -1070325008, tf_cs = 8, tf_eflags = 66178, tf_esp =
>>0, tf_ss = -1068146900})
>>    at /usr/src/sys/i386/i386/trap.c:418
>>#9  0xc04dd9e8 in calltrap () at {standard input}:102
>>#10 0xc04adbde in vm_page_sleep_if_busy (m=0x1b9, also_m_busy=1, msg=0x0)
>>    at /usr/src/sys/vm/vm_page.c:441
>>#11 0xc04abcfb in vm_object_split (entry=0xc6eea8ac)
>>    at /usr/src/sys/vm/vm_object.c:1226
>>...
>>    
>>
>
>Based upon the above information, it looks like vm_object_split()
>followed a bogus vm page pointer.  This is in frequently executed
>code.  So, I would hypothesize a race condition or transient hardware
>error is responsible.
>
>When my recent amd64 and i386 pmap changes are replicated on all
>platforms that will enable me to introduce additional assertions on
>the vm object locking.  That may reveal some unsynchronized vm object
>accesses that could lead to the above problem.
>
>Alan
>_______________________________________________
>  
>
FWIW, I got this same panic a few days ago, running portinstall shortly 
after gnome2 had fillled my fd table for some unknown reason, on 
5.1-RELEASE-p5.

Adam