Date: Sun, 10 Apr 2005 12:42:20 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: ltning@anduin.net Cc: stable@freebsd.org Subject: Re: Panic when logging out from serial console Message-ID: <20050410124013.W4310@fledge.watson.org> In-Reply-To: <20050410102753.d63hhe8vpcs8wsgg@anduin.net> References: <20050410102753.d63hhe8vpcs8wsgg@anduin.net>
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On Sun, 10 Apr 2005 ltning@anduin.net wrote: > warning: This report might be somewhat vague. For quite a while now I`ve > been plagued with the problem that logging out from a serial console > causes the box to panic. For a while I`ve been sure this was isolated to > one of my boxen, because it`s been acting up in other ways as well, but > today it happened on two other boxes too! And these boxes have been rock > stable for the last two years. > > I`m running a fairly recent variation of RELENG-5 on all the boxes; one > of them is amd64, the two others - including the one I`ve pasted from - > are plain old p3 machines. They are all dual-CPU though. I've seen precisely this panic -- in fact, I saw it yesterday on a RELENG_5 box, and under identical circumstances -- it looks like it happens if a last process in a login session on a serial console closes the tty, and then getty re-opens it while there's console output coming from syslog. I was able to get a core dump, but haven't made much headway on it yet. It looks like the tty structure has been released -- the refcount on the tty is 0, and the mutex pointers in the kqueue state have been cleared (hence the null pointer dereference you see). Now, the question is why -- I've added some debugging output to the local box I saw it on, and will see if I can reproduce it. Robert N M Watson > > I have no clue what I can do from here; has anyone seen this before? I can`t > always reproduce it, but the risk is fairly high - around 33% I`d say. > > Anyone? > > Thanks for your attention, details below. > > Fatal trap 12: page fault while in kernel mode > cpuid = 1; apic id = 00 > fault virtual address = 0x1c > fault code = supervisor write, page not present > instruction pointer = 0x8:0xc0620b5f > stack pointer = 0x10:0xdadbd988 > frame pointer = 0x10:0xdadbd994 > code segment = base 0x0, limit 0xfffff, type 0x1b > = DPL 0, pres 1, def32 1, gran 1 > processor eflags = interrupt enabled, resume, IOPL = 0 > current process = 51999 (getty) > trap number = 12 > panic: page fault > cpuid = 1 > boot() called on cpu#0 > Uptime: 66d11h24m50s > > > > /Eirik > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program. > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >
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