Date: Mon, 2 Sep 2013 10:16:43 +0400 From: Dmitry Sivachenko <trtrmitya@gmail.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: stable@freebsd.org Subject: Re: 9-STABLE panic on intensive fork Message-ID: <99023A4B-AA44-45DD-B163-D9FF23E7AEA4@gmail.com> In-Reply-To: <20130829184515.GN4972@kib.kiev.ua> References: <CC172316-C1A0-496A-ABEA-16A9516C3467@FreeBSD.org> <20130829184515.GN4972@kib.kiev.ua>
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On 29.08.2013, at 22:45, Konstantin Belousov <kostikbel@gmail.com> wrote: > On Wed, Aug 28, 2013 at 06:20:29PM +0400, Dmitry Sivachenko wrote: >> Hello! >> >> I am using very recent FreeBSD-9-STABLE snapshot: >> 9.2-PRERELEASE FreeBSD 9.2-PRERELEASE #0 r254986: Wed Aug 28 17:18:57 MSK 2013 >> >> I run uwsgi program (ports/www/uwsgi) on that machine. >> >> When uwsgi starts, it forks pre-configured number of worker processes. >> If I raise workers parameter high enough (128), I get kernel panic (100% reproducible): >> >> Fatal trap 12: page fault while in kernel mode >> >> If I compile kernel with KDB enabled, I get the following stack: >> >> pmap_demote_pde_locked() >> pmap_copy() >> vmspace_fork() >> fork1() >> sys_fork() >> >> I have only remote console for that machine, so I made 2 screenshots: >> >> 1) http://people.freebsd.org/~demon/screen1.jpg >> Panic screen when kernel has no KDB support compiled in >> >> 2) http://people.freebsd.org/~demon/screen2.jpg >> Panic screen (2nd part) with the above stack shown. > Look up the source line for the pmap_demote_pde_locked()+0x471 for your > kernel. Dump the core from the panic. Kernel dump is not generated (despite it is configured at boot), there is no "Dumping...." message on console. These screenshots shows everything I see on console. I performed some more investigations on this: I have several (14) totally identical configured machines running exactly the same software. Hardware is a bit different though. I tried to analyze motherboard differences but failed to find common things for the affected machines. Under conditions described in my initial e-mail, some of them crash (exactly the same way), some of them do not. I am confident there is no hardware problems, these machines run for months without reboot, as for now I discovered the only way to crash them. I updated one of the affected servers to 10-current and I can state it does not crash anymore with the same usage scenario.help
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