Date: Thu, 27 Aug 1998 10:14:19 +0300 (EEST) From: Alexander Litvin <archer@lucky.net> To: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> Cc: current@FreeBSD.ORG Subject: Re: encountered possible VM bug ? Message-ID: <199808270714.KAA02669@grape.carrier.kiev.ua> In-Reply-To: <19980824111923.A207@compufit.at> <19980824115816.A15512@mars.hsc.fr> <199808241413.KAA26862@khavrinen.lcs.mit.edu>
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In article <199808241413.KAA26862@khavrinen.lcs.mit.edu> you wrote: GW> <<On Mon, 24 Aug 1998 11:58:16 +0200, Pierre Beyssac <Pierre.Beyssac@hsc.fr> said: >> Under out of memory conditions, inetd tends to fall in a weird >> state. Apparently this is an interaction between the malloc library >> and inetd, but nobody has managed yet to find out exactly what >> happens. Maybe error checking is lacking somewhere. GW> No, this is the ``daemons dying'' bug which nobody has fixed yet. GW> When the system runs out of swap, some random selection of processes GW> which are in swap get corrupted. Usually this results in a daemon GW> which dies whenever it fork()s, but sometimes it is manifested as GW> other sorts of corruption. The message you see from realloc is GW> indicative of a corrupted pointer. Really, I was under impression, that it is the problem just with fork(). But now I may confirm that processes get corrupted in different manners. E.g., I have now a specially written dummy daemon running, which I was able to corrupt (intentionally exhausting swap) in such a way that it successfully forks. Than child process sleeps (just to give me chance to attach to it with debugger), allocates memory, accesses it -- and during all that it doesn't get SIGSEGV. But then it dies when trying to syslog(3). It seems that the corruption is in mmaped ld.so or libc.3.1.so. If anybody cares, I may try to give any other details. GW> -GAWollman SY, Alexander Litvin, Lucky Net ltd. --- According to Kentucky state law, every person must take a bath at least once a year. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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