Date: Wed, 06 Feb 2002 23:32:37 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Bruce Evans <bde@zeta.org.au> Cc: Bruce Evans <bde@FreeBSD.org>, cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Subject: RE: cvs commit: src/sys/i386/i386 db_interface.c Message-ID: <XFMail.020206233237.jhb@FreeBSD.org> In-Reply-To: <20020206201716.B2295-100000@gamplex.bde.org>
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On 06-Feb-02 Bruce Evans wrote: > On Tue, 5 Feb 2002, John Baldwin wrote: > >> On 05-Feb-02 Bruce Evans wrote: >> > On Tue, 5 Feb 2002, John Baldwin wrote: >> >> Err, have you tested this? In my tests locally this still doesn't work >> >> properly which is why I haven't committed it. :( >> > >> > PS: perhaps you are thinking of the flag in Debugger(). That is >> > ... >> >> Hmm, the problem I was having is that interrupts were still firing while I >> was >> in ddb. I could tell because new KTR entries due to clock interrutps kept >> showing up. > > This can't happen :-). Except for bugs which would affect most forms > of interrupt disablement. Perhaps there is a path through trap() which > enables interrupts even for debugger traps, but only when they are > enabled when the trap occurs. Ah, I see a related broken path, not > for debugger traps but for pagefaults. Interrupts are enabled for > pagefaults almost unconditionally, so a pagefault in ddb would cause > problems. I think this causes the "Context switches not allowed in the > Debugger" message. I thought that this was caused by a more fundamental > bug. Hmm, agreed that we shouldn't re-enable interrupts unless they were enabled in the previous frame. I'll test this out again locally to see if I still have problems though. > BTW, why does the spinlocking in kern_clock.c use MTX_QUIET? nanotime() > for witness timestamps should work normally there. I noticed this > when I uninlined mtx_*_spin_*(). The `flags' versions are not used > anywhere else. Because if you are trying to debug locks using KTR_LOCK you get lots of noise from the clock interrupts. :) > Bruce -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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