Re: netgraph calling VFS from network swi (was: Re: 5.2-RC fatal trap 12)

From: Alexander Motin (mav_at_alkar.net)
Date: 12/12/03

  • Next message: Alexander Zagrebin: "RELENG_5_2 ntfs mounting problem"
    Date: Fri, 12 Dec 2003 20:25:45 +0200
    To: Robert Watson <rwatson@freebsd.org>
    
    

    Robert Watson wrote:
    >>>Same problem on other hardware but on system booted from same HDD:
    >>
    >>This is a really scary stack trace -- it looks like netgraph is calling
    >>into the kernel linker from the network swi, and that in turn is hitting
    >>VFS. I may have missed earlier messages in this thread, but do you have a
    >>precise list of userland activities you're performing to trigger this? It
    >>looks like you're doing something that causes netgraph to load additional
    >>modules... Which would probably not be such a bad thing if it happened in
    >>a different thread context.

    This happend when I try to use mpd daemon as PPPoE server. It works fine
    on 4.9, but crashes on 5.2-RC.
    At that time I really did not have all NG modules loaded. In 4.9 all
    required modules was loaded automatically.

    > FYI, you can probably work around the panic by preloading whatever module
    > it's trying to load, such that the module is already available when the
    > trigger event happens and it doesn't try to load the module in that
    > context.

    If I preload at least ng_tee then system don't crashes but mpd still
    dont work. :( But this is other question.

    PS: One time when I try to unload ng_socket I got other kernel trap:

    Fatal trap 12: page fault while in kernel mode
    cpuid = 0; apic id = 00
    fault virtual address = 0xc417b2f4
    fault code = supervisor read, page not present
    instruction pointer = 0x8:0xc05b3bb0
    stack pointer = 0x10:0xd2a38c98
    frame pointer = 0x10:0xd2a38cb0
    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 = 27 (swi8: tty:sio clock)
    trap number = 12
    panic: page fault
    cpuid = 0;

    syncing disks, buffers remaining... 3020 3020 3020 3020 3020 3020 3020
    3020 3020 3020 3020 3020 3020 3020 3020 3020 3020 3020 3020 3020
    giving up on 176 buffers
    Uptime: 1h18m15s
    Dumping 383 MB
      16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256 272 288 304
    320 336 352 368

    ---
    #0  doadump () at ../../../kern/kern_shutdown.c:240
    240             dumping++;
    Ready to go.  Enter 'tr' to connect to remote target
    and 'getsyms' after connection to load kld symbols.
    (kgdb) bt
    #0  doadump () at ../../../kern/kern_shutdown.c:240
    #1  0xc0576661 in boot (howto=0x100) at ../../../kern/kern_shutdown.c:372
    #2  0xc0576a3e in panic () at ../../../kern/kern_shutdown.c:550
    #3  0xc06d32cc in trap_fatal (frame=0xd2a38c58, eva=0x0) at 
    ../../../i386/i386/trap.c:821
    #4  0xc06d2f72 in trap_pfault (frame=0xd2a38c58, usermode=0x0, 
    eva=0xc417b2f4) at ../../../i386/i386/trap.c:735
    #5  0xc06d2b83 in trap (frame=
           {tf_fs = 0xc07b0018, tf_es = 0xd2a30010, tf_ds = 0xc0590010, 
    tf_edi = 0xc05b3b90, tf_esi = 0xc417b2e0, tf_ebp = 0xd2a38cb0, tf_isp = 
    0xd2a38c84, tf_ebx = 0x6, tf_edx = 0x0, tf_ecx = 0xd8, tf_eax = 0x10000, 
    tf_trapno = 0xc, tf_err = 0x0, tf_eip = 0xc05b3bb0, tf_cs = 0x8, 
    tf_eflags = 0x10282, tf_esp = 0x8, tf_ss = 0xc071a1a5})
         at ../../../i386/i386/trap.c:420
    #6  0xc06bfd78 in calltrap () at {standard input}:94
    #7  0xc0587018 in softclock (dummy=0x0) at ../../../kern/kern_timeout.c:225
    #8  0xc05631f2 in ithread_loop (arg=0xc39de380) at 
    ../../../kern/kern_intr.c:544
    #9  0xc05621a4 in fork_exit (callout=0xc0563060 <ithread_loop>, arg=0x0, 
    frame=0x0) at ../../../kern/kern_fork.c:793
    -- 
    Alexander Motin mav@alkar.net
    ISP "Alkar-Teleport"
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