Date: Sat, 09 Feb 2013 21:52:21 +0400 From: Sevan / Venture37 <venture37@gmail.com> To: freebsd-current@freebsd.org Subject: Re: [patch] Userland DTrace Message-ID: <51168CD5.5050907@gmail.com> In-Reply-To: <51152216.9080905@icritical.com> References: <51152216.9080905@icritical.com>
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On 08/02/2013 20:04, Matt Burke wrote: > I've been spending some time trying to get the fasttrap provider to work > on FreeBSD without panicing. I believe I have succeeded, at least to the > point where it's no longer panicing. > > There were two panic causes. The first was > http://www.freebsd.org/cgi/query-pr.cgi?pr=165541 - the FreeBSD port of > fasttrap.c caused ftp_rcount to be left >0. To fix this I've got rid of > the early return and reverted to the opensolaris way. > > A second panic then showed up intermittently when fasttrap_pid_cleanup_cb > was run while something in userland had locks. Using sx_try_xlock calls > has stopped the panics and shouldn't affect operation AFAICT. > > This is against r246454. > > > Although this has fixed the panics for me, I'm finding a lot of stuff just > isn't actually working, with dtrace and the traced process just chewing > CPU. Truss on the dtrace shows a heck of a lot of ptrace() calls and I > have no idea what the target is doing... CPU time is split 2:1 > dtrace:target > > > Also noteworthy is the LOR on the first time you try to use the fasttrap > provider: http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/165479 > > The lock order there seems right, so I'm guessing "something else" must > have done it wrong first? How can I find out what the "something else" > is? Hi Matt, It might be worth posting the question to the dtrace list if your question is unanswered. http://dtrace.org/blogs/mailing-list/ Regards, Sevan
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