Re: kern/68442: panic - acquiring duplicate lock of same type: "sleepq chain"

On Tuesday 29 June 2004 11:39 am, Daniel Lang wrote:
> Hi again,
>
> Ok, here are some LOR's that occurred today on the machine
> before it paniced and wedged. The LOR's are not yet listed
> on the LOR page, so I cc: Bjoern.
>
> The panic and subsequent system wedge did not happen
> immediately after the LORs, the system continued to
> run for a while, but only for short while after the second LOR.
>
> Important INFO: I cvsuped and built new world and kernel
> (in single user mode, the system appears to be able to do
> some work in single user) of _today_. I hoped the problem might
> go away. I also removed KVA_PAGES=512 from kernel config,
> so default KVA_PAGES apply. It apparently did not help.
>
> LOR1:
> [..]
> login: lock order reversal
>  1st 0xc070a0c0 sched lock (sched lock) _at_ /usr/src/sys/kern/kern_proc.c:672
>  2nd 0xc0745d40 sio (sio) _at_ /usr/src/sys/dev/sio/sio.c:3205
> Stack backtrace:
> backtrace(ffffffff,c0712948,c0712b00,c06e25c4,c07358dc) at 0xc051e066 =
> backtra2 witness_checkorder(c0745d40,9,c06b1e34,c85,3f8) at 0xc05393c4 =
> witness_checkor4 _mtx_lock_spin_flags(c0745d40,0,c06b1e34,c85,c0712498) at
> 0xc0516e9e = _mtx_loce siocnputc(c06f9c40,63) at 0xc064375f =
> siocnputc+0x6b
> cnputc(63) at 0xc05483ed = cnputc+0x4d
> putchar(63,e5bd87e0) at 0xc053387a = putchar+0x92
> kvprintf(c069d236,c05337e8,e5bd87e0,a,e5bd8800) at 0xc0533a87 =
> kvprintf+0x77 printf(c069d236,32cf1,0,32ce6,0,dd8,c9115828) at 0xc0533763 =
> printf+0x43 calcru(c91156e0,e5bd8ad0,e5bd8ad8,0,e5bd8a10) at 0xc051cb9e =
> calcru+0x1f2
> fill_kinfo_thread(c436e930,e5bd88fc,e5bd8b98,c05194b6,c91156e0) at
> 0xc0518f2a =6 fill_kinfo_proc(c91156e0,e5bd88fc,dd8,288,0) at 0xc0518c01 =
> fill_kinfo_proc+0x1 sysctl_out_proc(c91156e0,e5bd8c08,4,0,4) at 0xc05194b6
> = sysctl_out_proc+0x32
> sysctl_kern_proc(c06e2c20,e5bd8c90,0,e5bd8c08,c06e2c20) at 0xc05199d8 =
> sysctl_4 sysctl_root(0,e5bd8c84,3,e5bd8c08,ca65fe70) at 0xc052519f =
> sysctl_root+0x10f userland_sysctl(ca65fe70,e5bd8c84,3,0,bfbfe47c) at
> 0xc052535c = userland_sysctlc __sysctl(ca65fe70,e5bd8d14,6,3,296) at
> 0xc052521d = __sysctl+0x71
> syscall(2f,2f,2f,3,0) at 0xc0664713 = syscall+0x217
> Xint0x80_syscall() at 0xc06539ff = Xint0x80_syscall+0x1f
> --- syscall (202), eip = 0x280dd05b, esp = 0xbfbfe40c, ebp = 0xbfbfe448 ---
> [..]
>
> LOR2:
> [..]
> acquiring duplicate lock of same type: "sleepq chain"
>  1st Giant _at_ /usr/src/sys/kern/uipc_syscalls.c:1735
>  2nd sleepq chain _at_ /usr/src/sys/kern/subr_sleepqueue.c:223

This message makes no sense at all as they aren't the same type.

> And here the panic message:
> [..]
> Fatal trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 06
> fault virtual address   = 0x34
> fault code              = supervisor read, page not present
> instruction pointer     = 0x8:0xc053932b
> stack pointer           = 0x10:0xe53d8ab0
> frame pointer           = 0x10:0xe53d8ad4
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, def32 1, gran 1
> processor eflags        = resume, IOPL = 0
> current process         = 2550 (cvsupd)
> [..]
>
> No ddb prompt, no crash-dump, no reboot. I need to go and
> reset the thing (now for the dozenth time :-/).

Can you pop up gdb -k on the kernel.debug and do 'l *0xc053932b'

-- 
John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org