Date: Wed, 23 Aug 2000 01:31:21 -0700 From: Dragos Ruiu <dr@dursec.com> To: Rick <wylee@sabrecross.com>, freebsd-security@freebsd.org Subject: Re: 3.5 and 4.0 with sendmail 8.9.3 Message-ID: <0008230135450N.36794@smp.kyx.net> In-Reply-To: <Pine.WNT.4.05.10008221124060.170-100000@lan.imbris.com> References: <Pine.WNT.4.05.10008221124060.170-100000@lan.imbris.com>
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Make a backup of the files that flake regularly. Create a watchdog that looks for the files flaking after a copy and copy from the backups in that case. Use a lock file or some other form of interlock to disable the watchdog during a copy so that the watchdog doesn't collide with a copy. Watchdog will wake up after the lock is removed and if the file is flaked, hopefully resore your system before it goes off the deep end again. But I'm sure there are other solutions, including using some sort of reliable protocol for the transfer so that the files don't flake in the first place. cheers, --dr On Tue, 22 Aug 2000, Rick wrote: > Fun problem? > > Wanna get a machine to reach max load and never return to normal? > Watch sendmail processes explode faster that you can refresh PS? > Try this? > > Here is what we have: tested two machines: Alpha 500a running 4.0 and I386 > running 3.5, only common attributes: BT-958 SCSI card and etherlink III > 10/100 cards. Which BTW the BT958 goes into mailbox busy, 192 commands, > scsi clear both machines, problem is confirmed with the BL driver. Doesn't > happen with an Adaptec. Note 3 versions of firmware for Busslogics was > tried on 3 seperate cards. All reacted the same. > > Mail is on one central server and aliase file along with password updates > are passed from another machine, via nfs, at various times during the day. > > 9/10 times not a problem all works as planned. > > when we fail: aliase.db file is not rebuilt and set to 0 bytes. > Aliase file is correct at proper value and number of bytes. > > Error message is aliase file is locked and can't run new aliases. > Now of coarse sendmail looking at the aliase file goes off the deep end > and attempts to do local delivery and can't. > > The only way so far to clear this problem is to shutdown now and do a > control D to bring back up in multi user. Forget reading the console port. > It scrolls faster than a 2K page running at DS3 speed. Nothing different > in the logs, either. > > Killing sendmail doesn't work. No locks can be found and until this occurs > system swears the file is locked. Not just locked in shared mode, but in > executive mode. > > Now we have tried a simple copy, a mv and various other ideas and the > problem is persistant on the regular aliase file. > > Today by varying the sequence the newliase command went off into space, > lost somewhere in the great memory void. The system did not attempt to > rebuild but the file did not say it was locked. Killed out of processes > ok. But could not rebuild aliase file. > > Again single user mode back to multi and you can clear, go about your > business. > > I stress the fact this is a random error. It may happen once in a 3 day > period or once every few hours. > > Any help would be appreciated. > > > > Rick McGee > Network Engineer > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-security" in the body of the message -- dursec.com ltd. / kyx.net - we're from the future pgp fingerprint: 18C7 E37C 2F94 E251 F18E B7DC 2B71 A73E D2E8 A56D pgp key: http://www.dursec.com/drkey.asc To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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