Date: Wed, 22 Sep 2004 17:36:25 +0900 From: Pyun YongHyeon <yongari@kt-is.co.kr> To: dhaigh@gatorzone.com Cc: sparc64@freebsd.org Subject: Re: PR sparc64/71729 Message-ID: <20040922083625.GA8910@kt-is.co.kr> In-Reply-To: <20040920104006.GA1905@kt-is.co.kr> References: <!~!UENERkVCMDkAAQACAAAAAAAAAAAAAAAAABgAAAAAAAAACQvSeqVn1BGUQgBglOsMr8KAAAAQAAAAcPmXkBll7EW4XKEqja5UUQEAAAAA@nc.rr.com> <20040920104006.GA1905@kt-is.co.kr>
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On Mon, Sep 20, 2004 at 07:40:06PM +0900, To dhaigh@gatorzone.com wrote: > On Fri, Sep 17, 2004 at 09:29:41AM -0400, Doug Haigh wrote: > > > > I am not sure if the PR got updated, but I wanted to let you know that the > > printf in a kernel thread only fails if you are on a SMP machine. It appears > > that if you printf on a CPU other than CPU #0, it will panic the kernel. > > > > After reading your mail, I made a small test program which creates > a kernel thread and ran it on AXe(UP) and U2(SMP). > Under AXe it worked as expected but it paniced on U2. > So it seems that there is some issues in OF console. > Backtrace for the panic is somthing like: > While looking into the ofw_console(4) code I noticed there is possible races there. So I patched the code and ran it. However it didn't fix the problem. Since we can't simply use a mutex in ofw_cons_putc(), there should be other way to workaround this. Have no idea yet. If you really really want to see your messages from a kernel thread you can do one of the following(tested on U2): 1. remove invocation of timeout(9) in ofw_console.c. With this modification, you can't enter characters with keyboard. 2. use sc + creator + uart + puc instead of ofw_console(4) On my U2, keyboard input didn't work. If you want to see my partial patch as a starting point please let me know. Cheers, Pyun YongHyeon -- Pyun YongHyeon <http://www.kr.freebsd.org/~yongari>;
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