From owner-freebsd-current@FreeBSD.ORG Sat Feb 14 00:58:06 2009 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 12DDB106564A for ; Sat, 14 Feb 2009 00:58:06 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id C639C8FC1D for ; Sat, 14 Feb 2009 00:58:05 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [65.122.17.41]) by cyrus.watson.org (Postfix) with ESMTPS id 68EDE46B0C; Fri, 13 Feb 2009 19:58:05 -0500 (EST) Date: Sat, 14 Feb 2009 00:58:05 +0000 (GMT) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Andrew Gallatin In-Reply-To: <4995A792.5050003@cs.duke.edu> Message-ID: References: <4995A792.5050003@cs.duke.edu> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: current@freebsd.org Subject: Re: Dtrace panic'ed X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Feb 2009 00:58:06 -0000 On Fri, 13 Feb 2009, Andrew Gallatin wrote: > I was trying to run a simple dtrace profiling script, and panic'ed the > machine using today's -current on an 8-way opteron. Oh, you actually got a panic using the profile provider? For me the box appears to go into la-la land. I've also seen a few double faults using fbt a bit too gratuitously. Unfortunately, I haven't found time to debug it, but I wondered if perhaps DTrace is not recognizing its own functions (i.e., ones it shouldn't try to trace) properly and/or failing to disable interrupts or enter a critical section at important moments. Robert N M Watson Computer Laboratory University of Cambridge > > I tried to run: > #!/usr/sbin/dtrace -s > > profile:::profile-997 > { > @a[stack(20)]=count(); > } > > END > { > trunc(@a, 20); > printa(@a); > } > > Everything was fine until I hit ^C. This appeared > on the tty (which I expected): > > dtrace: script '/nfs/home/gallatin/dtrace/profile_stack.d' matched 2 probes > ^C > CPU ID FUNCTION:NAME > 1 2 :END > > kernel`vm_page_splay+0x5b > kernel`trap+0x482 > kernel`0xffffffff807eb8f3 > 1 > > kernel`vm_fault+0x1e2 > 1 > > kernel`pagezero+0x17 > 1 > > kernel`cpu_idle+0x1 > 1 > > kernel`pmap_enter+0x6f > kernel`0xffffffff807eb8f3 > 1 > > 4 > > kernel`pagezero+0x11 > 4 > > kernel`acpi_cpu_c1+0x6 > kernel`0xffffffff807ebd4e > 14063 > > And then the machine fell over with this on console: > > kernel trap 12 with interrupts disabled > > > Fatal trap 12: page fault while in kernel mode > cpuid = 7; apic id = 07 > fault virtual address = 0x20 > fault code = supervisor read data, page not present > instruction pointer = 0x8:0xffffffff80e33187 > stack pointer = 0x10:0xfffffffe4004aa70 > frame pointer = 0x10:0xfffffffe4004aa80 > code segment = base 0x0, limit 0xfffff, type 0x1b > = DPL 0, pres 1, long 1, def32 0, gran 1 > processor eflags = resume, IOPL = 0 > current process = 11 (idle: cpu7) > trap number = 12 > panic: page fault > cpuid = 7 > KDB: stack backtrace: > db_trace_self_wrapper() at db_trace_self_wrapper+0x2a > panic() at panic+0x182 > trap_fatal() at trap_fatal+0x2ad > trap_pfault() at trap_pfault+0x294 > trap() at trap+0x38b > calltrap() at calltrap+0x8 > --- trap 0xc, rip = 0xffffffff80e33187, rsp = 0xfffffffe4004aa70, rbp = > 0xfffffffe4004aa80 --- > cyclic_disable_xcall() at cyclic_disable_xcall+0x7 > smp_rendezvous_action() at smp_rendezvous_action+0xb3 > Xrendezvous() at Xrendezvous+0x64 > --- interrupt, rip = 0xffffffff807e3cf6, rsp = 0xfffffffe4004ab70, rbp = > 0xfffffffe4004ab80 --- > acpi_cpu_c1() at acpi_cpu_c1+0x6 > acpi_cpu_idle() at acpi_cpu_idle+0x19c > sched_idletd() at sched_idletd+0x234 > fork_exit() at fork_exit+0x118 > fork_trampoline() at fork_trampoline+0xe > --- trap 0, rip = 0, rsp = 0xfffffffe4004ad40, rbp = 0 --- > Uptime: 5m14s > Physical memory: 8177 MB > Dumping 506 MB: 491 475 459 443 427 411 395 379 363 347 331 315 299 283 267 > 251 235 219 203 187 171 155 139 123 107 91 75 59 43 27 11 > > > Cheers, > > Drew > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >