Date: Mon, 23 Feb 2009 11:19:54 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: David Christensen <davidch@broadcom.com> Subject: Re: Hopefully Simple Question on Debugging Kernel Modules Message-ID: <200902231119.54925.jhb@freebsd.org> In-Reply-To: <5D267A3F22FD854F8F48B3D2B5238193394588D54D@IRVEXCHCCR01.corp.ad.broadcom.com> References: <5D267A3F22FD854F8F48B3D2B5238193394588D54D@IRVEXCHCCR01.corp.ad.broadcom.com>
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On Friday 20 February 2009 6:40:56 pm David Christensen wrote: > I'm sure this is a simple question but the answer is alluding my Google > search capabilities. My driver is being loaded as a kernel module and > is failing with the following error: > > Fatal trap 12: page fault while in kernel mode > cpuid = 0; apic id = 00 > fault virtual address = 0xfffffffe40abe9dc > fault code = supervisor write data, page not present > instruction pointer = 0x8:0xffffffff920b638f > stack pointer = 0x10:0xffffffff9212bb10 > frame pointer = 0x10:0xffffffff9212bbb0 > 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 (irq268: bce0) > [thread pid 12 tid 100166 ] > Stopped at bce_intr+0x8df: addl $0x1,0x2c854(%r12,%rax,4) > db> > > I simply need to find the offending source line in my driver. Not sure > how I've managed to get the driver running at all without this but it's > time to do things the right way. I have KDB/DDB/GDB built into my > -CURRENT kernel already. It'd be great to find the source line while in > the kernel debugger but I'm also fine with rebooting the system to > identify the line number. Just use gdb on bce.ko (built with debug symbols): gdb /path/to/if_bce.ko (gdb) l *bce_intr+0x8df If you get a crashdump you can run kgdb on it and just walk up to the relevant stack frame and use 'l' there to get a listing. -- John Baldwin
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