Date: Wed, 1 May 2013 19:08:57 +0100 From: "Robert N. M. Watson" <rwatson@freebsd.org> To: Glen Barber <gjb@FreeBSD.org> Cc: Ian FREISLICH <ianf@clue.co.za>, freebsd-current@freebsd.org Subject: Re: panic: in_pcblookup_local (?) Message-ID: <49916D2B-496A-40EA-971F-62951FF6B584@freebsd.org> In-Reply-To: <20130501180321.GA44525@glenbarber.us> References: <E1UW0K5-000P7H-36@clue.co.za> <201304301653.13845.jhb@freebsd.org> <20130430211908.GB1621@glenbarber.us> <201305011156.03974.jhb@freebsd.org> <F33F9F1A-1905-480B-A22B-8995B9772B51@freebsd.org> <20130501180321.GA44525@glenbarber.us>
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On 1 May 2013, at 19:03, Glen Barber wrote: >> I'll need to catch up on this thread later, but a few questions: >>=20 >> Do we know if the application in question is multithreaded, and >> if so, might it be attempting concurrent operations on this socket? >=20 > I do not know if zabbix-agent is multithreaded, but cf-agent is. If in DDB, it would be useful to do a "ps" so we can identify threads in = the process, and in particular, whether they might be in the kernel = around the moment of the panic. > I will follow up with this information as soon as possible. Thanks. Do keep around as much information as you can from DDB, = crashdumps, etc. A useful set of things to keep from DDB includes the = initial panic information and trap frame, "show pcpu", "show allpcpu", = "trace", "alltrace", "ps", and if WITNESS is compiled in, "show locks" = and "show alllocks". On busy systems, all the backtraces add up to a lot = of space, so you might hold onto that rather than e-mail it, but contain = useful information. Often, debugging this sort of race condition = involves looking at what other network-centred threads are doing -- = e.g., device-driver ithreads, netisr, other involved user threads. You = may be able to extract much of that information using ps on the = crashdump (not sure if procstat is there yet for crashdumps) -- if so, = be sure to use -H (or whatever the argument is to print thread, not just = process, information). Off to a formal dinner, but back later! Robert=
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