Date: Sat, 19 Aug 2000 19:26:17 -0400 From: Bosko Milekic <bmilekic@technokratis.com> To: John Polstra <jdp@polstra.com>, dwmalone@freebsd.org Cc: current@freebsd.org Subject: Re: (URGENT) Instant panic in _MEXT_ALLOC_CNT Message-ID: <000501c00a34$dfd43f20$71cbc918@jehovah> References: <XFMail.000819152111.jdp@polstra.com>
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Hrmmm, there may be a logic problem here. Try this (apply it manually,
as I am not able to produce a diff at this time):
change:
if ((__mcnt == NULL) && (m_alloc_ref(1) == 0))
panic("mbuf subsystem: out of ref counts!");
to:
if (__mcnt == NULL) {
if (m_alloc_ref(1) != 0)
__mcnt = mext_refcnt_free;
else
panic("mbuf subsystem: out of ref counts!");
}
It could be that the m_alloc_ref(1) doesn't fail, but that __mcnt
is still NULL, it's missing that __mcnt = mext_refcnt_free assignment.
This is most probably a BUG, so please commit the fix...
If this does not solve the problem, we may be looking at a newly
uncovered problem in fxp, although I doubt this.
-Bosko
bmilekic@dsuper.net
----- Original Message -----
From: "John Polstra" <jdp@polstra.com>
To: <current@FreeBSD.ORG>
Sent: Saturday, August 19, 2000 6:21 PM
Subject: Instant panic in _MEXT_ALLOC_CNT
> With sources from this morning I am getting an instant kernel-mode
> page fault in the new mbuf cluster reference counting code. It is
> failing in this statement of _MEXT_ALLOC_CNT (sys/mbuf.h), as far as
> I can tell:
>
> #define _MEXT_ALLOC_CNT(m_cnt) MBUFLOCK( \
> union mext_refcnt *__mcnt; \
> \
> __mcnt = mext_refcnt_free; \
> if ((__mcnt == NULL) && (m_alloc_ref(1) == 0)) \
> panic("mbuf subsystem: out of ref counts!"); \
> mext_refcnt_free = __mcnt->next_ref; \
> [*crash*]
>
> Here is the console output and a stack trace from DDB:
>
> Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
> The Regents of the University of California. All rights reserved.
> FreeBSD 5.0-CURRENT #0: Sat Aug 19 14:49:39 PDT 2000
> jdp@blake.polstra.com:/local0/obj/local0/src/sys/BLAKE
> Timecounter "i8254" frequency 1193163 Hz
> Timecounter "TSC" frequency 400902857 Hz
> CPU: Pentium II/Pentium II Xeon/Celeron (400.90-MHz 686-class CPU)
> Origin = "GenuineIntel" Id = 0x653 Stepping = 3
>
>
Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,
PAT,PSE36
> ,MMX,FXSR>
> real memory = 134205440 (131060K bytes)
> avail memory = 127336448 (124352K bytes)
> Preloaded elf kernel "kernel" at 0xc034b000.
> Pentium Pro MTRR support enabled
> npx0: <math processor> on motherboard
> npx0: INT 16 interface
> pcib0: <Intel 82443BX (440 BX) host to PCI bridge> on motherboard
> pci0: <PCI bus> on pcib0
> pci0: <Intel 82443BX (440 BX) host to PCI bridge> at 0.0
> pcib1: <Intel 82443BX (440 BX) PCI-PCI (AGP) bridge> at device 1.0 on pci0
> pci1: <PCI bus> on pcib1
> pci1: <Matrox MGA G400 AGP graphics accelerator> at 0.0 irq 11
> isab0: <Intel 82371AB PCI to ISA bridge> at device 4.0 on pci0
> isa0: <ISA bus> on isab0
> pci0: <Intel PIIX4 ATA controller> at 4.1
> pci0: <Intel 82371AB/EB (PIIX4) USB controller> at 4.2
> intpm0: <Intel 82371AB Power management controller> port 0xe800-0xe80f irq
9 at
> device 4.3 on pci0
> intpm0: I/O mapped e800
> intpm0: intr IRQ 9 enabled revision 0
> smbus0: <System Management Bus> on intsmb0
> smb0: <SMBus general purpose I/O> on smbus0
> intpm0: PM I/O mapped e400
> ahc0: <Adaptec aic7890/91 Ultra2 SCSI adapter> port 0xd000-0xd0ff mem
> 0xe0000000-0xe0000fff irq 5 at device 6.0 on pci0
> ahc0: aic7890/91 Wide Channel A, SCSI Id=7, 32/255 SCBs
> fxp0: <Intel Pro 10/100B/100+ Ethernet> port 0xb800-0xb83f mem
> 0xdf000000-0xdf0fffff,0xdf800000-0xdf800fff irq 12 at device 10.
> 0 on pci0
>
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address = 0x0
> fault code = supervisor read, page not present
> instruction pointer = 0x8:0xc02126ac
> stack pointer = 0x10:0xc035fea8
> frame pointer = 0x10:0xc035febc
> code segment = base 0x0, limit 0xfffff, type 0x1b
> = DPL 0, pres 1, def32 1, gran 1
> processor eflags = interrupt enabled, resume, IOPL = 0
> current process = 0 (swapper)
> interrupt mask = net tty bio cam
> kernel: type 12 trap, code=0
> Stopped at fxp_add_rfabuf+0x170: movl 0(%ebx),%eax
> db> trace
> fxp_add_rfabuf(c0a52c00,0) at fxp_add_rfabuf+0x170
> fxp_attach_common(c0a52c00,c0a52cd8) at fxp_attach_common+0xb8
> fxp_attach(c0a4ad80,c0a4ad80,c0a49600,c0a49580,0) at fxp_attach+0x1ad
> device_probe_and_attach(c0a4ad80) at device_probe_and_attach+0x8e
> bus_generic_attach(c0a49580,c0a49580,c0a49700,c0a49600,0) at
bus_generic_attach+0x16
> device_probe_and_attach(c0a49580) at device_probe_and_attach+0x8e
> bus_generic_attach(c0a49600,c0a49600,c071b680,c0a49700,0) at
bus_generic_attach+0x16
> device_probe_and_attach(c0a49600) at device_probe_and_attach+0x8e
> bus_generic_attach(c0a49700,c0a35080,c035ffc0,c0170c46,c0a49700) at
> bus_generic_attach+0x16
> nexus_attach(c0a49700,c0a49700,c02c0e10,364000,0) at nexus_attach+0xd
> device_probe_and_attach(c0a49700) at device_probe_and_attach+0x8e
> root_bus_configure(c071b680,c029bacc,0) at root_bus_configure+0x16
> configure(0,35dc00,364000,0,c011dc09) at configure+0x33
> mi_startup(0,0,0,0,0) at mi_startup+0x68
> begin() at begin+0x30
>
>
> John
> --
> John Polstra
jdp@polstra.com
> John D. Polstra & Co., Inc. Seattle, Washington
USA
> "Disappointment is a good sign of basic intelligence." -- Chögyam
Trungpa
>
>
>
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