From owner-freebsd-current Fri Mar 30 15: 2: 0 2001 Delivered-To: freebsd-current@freebsd.org Received: from meow.osd.bsdi.com (meow.osd.bsdi.com [204.216.28.88]) by hub.freebsd.org (Postfix) with ESMTP id 2A9CE37B71B for ; Fri, 30 Mar 2001 15:01:52 -0800 (PST) (envelope-from jhb@FreeBSD.org) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by meow.osd.bsdi.com (8.11.2/8.11.2) with ESMTP id f2UN1hG78492; Fri, 30 Mar 2001 15:01:43 -0800 (PST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Fri, 30 Mar 2001 15:01:19 -0800 (PST) From: John Baldwin To: Matthew Jacob Subject: RE: hmm.... spinlocks.. Cc: current@FreeBSD.org Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 30-Mar-01 Matthew Jacob wrote: > > > pic_initialize(): > lint0: 0x00010700 lint1: 0x00010400 TPR: 0x00000010 SVR: 0x000001ff > kernel trap 12 with interrupts disabled > panic: spin lock sched lock held by 0xc7ba8a60 for > 5 seconds > cpuid = 0; lapic.id = 00000000 > Debugger("panic") > > CPU0 stopping CPUs: 0x00000002... stopped. > Stopped at Debugger+0x45: pushl %ebx > db> t > Debugger(c02e3759) at Debugger+0x45 > panic(c02e2d60,c02fb929,c7ba8a60,c7ba7b80,fffea000) at panic+0xd0 > _mtx_lock_spin(c0357400,0,80246,c02e3a48,2fb) at _mtx_lock_spin+0x6e > wakeup(c3709378,c3709378,c0eec000,c0f71400,c3709454) at wakeup+0x67 > bufdone(c3709378,c7fbff40,c0131efb,c3709378,c0f71400) at bufdone+0x385 > bufdonebio(c3709378) at bufdonebio+0xe > dadone(c0f5d100,c0f71400) at dadone+0x1f7 > camisr(c032a834) at camisr+0x231 > ithread_loop(c0b2f080,c7fbffa8) at ithread_loop+0x247 > fork_exit(c019898c,c0b2f080,c7fbffa8) at fork_exit+0x83 > fork_trampoline() at fork_trampoline+0x8 Did you get a crashdump (probably not.) If you look at sched_lock, one of the words will be a pointer to the process owning the lock in question. Unfortunately it's not the first word anymore (something I may change in the future). On the alpha it would be 'sched_lock+48'. The pointer there points to the process owning the lock (and you can look up the process via ps). If you have a crash dump then I have some gdb macros that make it easy to get a backtrace of that process. If not, then, well, it gets harder. :-P Hmm, it might be nice to be able to ask ddb to give a backtrace of any arbitrary process. Maybe I'll add a new command for that.. The trick is that we want to know who grabbed sched_lock where and then started spinning with it. Using KTR with KTR_LOCK turned on and using the 'show ktr' command in ddb could also be used to see which process was the last to grab sched_lock and where it was grabbed. -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message