Date: Thu, 8 Jan 2009 22:44:20 -0500 (EST) From: Daniel Eischen <eischen@vigrid.com> To: Brian Fundakowski Feldman <green@freebsd.org> Cc: hackers@freebsd.org, jasone@freebsd.org Subject: Re: threaded, forked, rethreaded processes will deadlock Message-ID: <Pine.GSO.4.64.0901082237001.28531@sea.ntplx.net> In-Reply-To: <20090109031942.GA2825@green.homeunix.org> References: <20090109031942.GA2825@green.homeunix.org>
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This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --VbJkn9YxBvnuCH5J Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Content-ID: <Pine.GSO.4.64.0901082237003.28531@sea.ntplx.net> Content-Disposition: inline On Thu, 8 Jan 2009, Brian Fundakowski Feldman wrote: > It appears that the post-fork hooks for malloc(3) are somewhat broken such that > when a threaded program forks, and then its child attempts to go threaded, it > deadlocks because it already appears to have locks held. I am not familiar > enough with the current libthr/libc/rtld-elf interaction that I've been able > to fix it myself, unfortunately. There's really nothing to fix - according to POSIX you are only allowed to call async-signal-safe functions in the child forked from a threaded process. If you are trying to do anything other than that, it may or may not work on FreeBSD, but it is not guaranteed and is not portable. The rationale is that what is the point of forking and creating more threads, when you can just as easily create more threads in the parent without forking? The only reason to fork from a threaded process is to call one of the exec() functions. -- DE --VbJkn9YxBvnuCH5J Content-Type: TEXT/PLAIN; charset=us-ascii Content-ID: <Pine.GSO.4.64.0901082237004.28531@sea.ntplx.net> Content-Description: Content-Disposition: inline _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" --VbJkn9YxBvnuCH5J--
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