Date: Wed, 26 Jul 2006 01:07:21 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: Jack Vogel <jfvogel@gmail.com> Cc: freebsd-current@freebsd.org Subject: Re: em(4) watchdog timeout Message-ID: <20060725230721.GL6253@obiwan.tataz.chchile.org> In-Reply-To: <2a41acea0607251119i33176020pfc4183ecd2251dd2@mail.gmail.com> References: <20060721123448.GV6253@obiwan.tataz.chchile.org> <44C1CE73.7030200@FreeBSD.org> <20060725124328.GI6253@obiwan.tataz.chchile.org> <2a41acea0607251119i33176020pfc4183ecd2251dd2@mail.gmail.com>
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Jack, others, On Tue, Jul 25, 2006 at 11:19:22AM -0700, Jack Vogel wrote: > On 7/25/06, Jeremie Le Hen <jeremie@le-hen.org> wrote: > >I am rebuilding a fresher one right now. According to Ian's post, > >the problem is likely to remain. What do you advice me to do to > >track this down ? > > > >FYI, my -CURRENT kernel (as well userland) is patched with ProPolice. > >I don't think this can lead to this kind of problem, the overhead is > >really small, in an order of 3 percent. Do you think such an > >overhead in a time-critial path could trigger a watchdog timeout ? > > Well, watchdogs ARE about timeouts :) > > I know nothing about ProPolice but would suggest removing for a test > and see if the problem goes away. As a matter of fact ProPolice protects stack-based buffer overflows by pushing an additional value in the stack during vulnerable functions' prologue and checking it within the epilogue. This is really a matter of a few CPU cycles. Nevertheless, I will try to reproduce the problem as-is and will also recompile my kernel without ProPolice ASAP. > As for the debug_info and stats data you sent, there was nothing that > looked bad in it, but those are more of a dynamic tool, its when the > problem occurs that this will possibly show why.... I know, it doesnt > make it easy :( It would be a pain to do it manually, I will try to write a small script thates watch over dmesg and issues a few sysctl on debug_info whenever it detects a watch dog timeout. Thank you. Regards, -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >
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