Date: Fri, 26 Sep 2003 00:54:22 -0500 From: Alan Cox <alc@cs.rice.edu> To: Robert Watson <rwatson@FreeBSD.org> Cc: current@FreeBSD.org Subject: Re: panic on yesterday's -CURRENT: linux emulation and vm (lockmgr: locking against myself) Message-ID: <20030926055422.GB25202@noel.cs.rice.edu> In-Reply-To: <Pine.NEB.3.96L.1030925111156.50146A-100000@fledge.watson.org> References: <Pine.NEB.3.96L.1030925111156.50146A-100000@fledge.watson.org>
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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
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