Date: Thu, 29 Aug 2013 18:20:29 -0400 From: Mark Johnston <markj@freebsd.org> To: Andriy Gapon <avg@FreeBSD.org> Cc: freebsd-dtrace@FreeBSD.org Subject: Re: sdt deadlock Message-ID: <20130829221950.GA47468@raichu> In-Reply-To: <521F29F2.2020208@FreeBSD.org> References: <521F29F2.2020208@FreeBSD.org>
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On Thu, Aug 29, 2013 at 02:01:06PM +0300, Andriy Gapon wrote: > > We've just experienced a deadlock between dtrace_lock and sdt_sx. > > Mark, could you please take a look at the following debugging data if you have > some time? Does it look like something that could be fixed by your recent big > change to the related code? Hi Andriy, It will definitely be fixed by my recent changes - the sdt rewrite removed sdt_sx. :) Now the sdt code relies only on the kld lock and the DTrace locks, and I was careful to avoid LORs. In particular, the kld lock is always taken before any DTrace locks. I also just did a little test where I was loading and unloading a file containing SDT probe definitions in a loop, and running DTrace scripts in another terminal. I didn't have any problems, so I'm fairly confident that this particular interaction works properly now.
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