Date: Fri, 31 Aug 2007 03:20:55 -0700 (PDT) From: Martha Pasikatan <magpasikat@yahoo.com> To: freebsd-net@freebsd.org Subject: Panic experienced in ng_snd_item Message-ID: <731920.7976.qm@web44906.mail.sp1.yahoo.com>
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Hi,
The system panicked while I was running a program that uses netgraph heavily. This is the panic that showed.
Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address = 0x10
fault code = supervisor read, page not present
instruction pointer = 0x8:0xffffffff804fa6c4
stack pointer = 0x10:0xffffffffa5641b30
frame pointer = 0x10:0xffffffff9a6cb0a0
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 12 (swi4: clock sio)
trap number = 12
panic: page fault
When I did list *0xffffffff804fa6c4, this is what appeared:
0xffffffff804fa6c4 is in ng_snd_item (/usr/src/sys/netgraph/ng_base.c:2172).
2167
2168 int
2169 ng_snd_item(item_p item, int flags)
2170 {
2171 hook_p hook = NGI_HOOK(item);
2172 node_p node = NGI_NODE(item);
2173 int queue, rw;
2174 struct ng_queue * ngq = &node->nd_input_queue;
2175 int error = 0;
2176
The backtrace shows
#0 doadump () at pcpu.h:172
#1 0x0000000000000004 in ?? ()
#2 0xffffffff804326f7 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#3 0xffffffff80432d91 in panic (fmt=0xffffff003dbbdbe0 "Xû=") at /usr/src/sys/kern/kern_shutdown.c:565
#4 0xffffffff8069726f in trap_fatal (frame=0xffffff003dbbdbe0, eva=18446742975233639256)
at /usr/src/sys/amd64/amd64/trap.c:660
#5 0xffffffff8069758f in trap_pfault (frame=0xffffffffa5641a80, usermode=0)
at /usr/src/sys/amd64/amd64/trap.c:573
#6 0xffffffff80697843 in trap (frame=
{tf_rdi = 0, tf_rsi = 0, tf_rdx = 582, tf_rcx = -1098475906080, tf_r8 = 1, tf_r9 = -1098475906080, tf_rax = 0, tf_rbx = 0, tf_rbp = -1704152928, tf_r10 = -2136924776, tf_r11 = 0, tf_r12 = 0, tf_r13 = 4, tf_r14 = 0, tf_r15 = -2142253296, tf_trapno = 12, tf_addr = 16, tf_flags = -1098475906080, tf_err = 0, tf_rip = -2142263612, tf_cs = 8, tf_rflags = 66178, tf_rsp = -1520166080, tf_ss = 0}) at /usr/src/sys/amd64/amd64/trap.c:352
#7 0xffffffff80682a2b in calltrap () at /usr/src/sys/amd64/amd64/exception.S:168
#8 0xffffffff804fa6c4 in ng_snd_item (item=0x0, flags=0) at /usr/src/sys/netgraph/ng_base.c:2170
#9 0xffffffff804423d5 in softclock (dummy=0x0) at /usr/src/sys/kern/kern_timeout.c:290
#10 0xffffffff80417e79 in ithread_loop (arg=0xffffff0000d0c960) at /usr/src/sys/kern/kern_intr.c:682
#11 0xffffffff80416617 in fork_exit (callout=0xffffffff80417d30 <ithread_loop>, arg=0xffffff0000d0c960,
frame=0xffffffffa5641c50) at /usr/src/sys/kern/kern_fork.c:821
#12 0xffffffff80682d8e in fork_trampoline () at /usr/src/sys/amd64/amd64/exception.S:394
I was surprised to find the ng_send_item having a null item passed as a parameter. I believe it can't have been a call from NG_FWD_ITEM because it checks for the validity of the parameters passed to it. It is likely that the calling function was ng_callout_trampoline.
Now, I'm at a loss as to where to proceed from here. Does anyone have an idea or clue as to what is causing this? Any help, suggestion, or advice is welcome.
Matt
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