On Fri, May 11, 2007 at 05:50:07PM -0700, Matthew Dillon wrote: > > :There is a small delay <2s. I ran a loop that switched between two > :IPs for about 15 minutes and nothing happened. > : > :The kernel buffer output in the corefile was from months ago. I only > :remembered because I did the same thing this time; shutdown now; > :umount /home; ifconfig re0 ... I don't know how this can be in a dump > :months after the fact unless there is stale data in my swap partition > :from my last coredump that hasn't been overwritten since I don't do > :very much swapping. This idea may be completely wrong. I am 100% > :certain that I'm not looking at a stale dump as strings on the kernel > :and vmcore show them as being from May 9, 2007. I am also certain > :that I was not ifconfig'ing any interface when this happened. > : > :Joe > > Sometimes the BIOS clears memory, sometimes it doesn't. If it doesn't, > then sometimes the dmesg text from previous boots will remain in > memory and be available. That's all. Power cycle and it all goes poof.
This is a laptop that has been power cycled at least a hundred times since that took place so it seems to me there's no way it was coming from memory. When my re(4) troubles were happening I had hw.physmem set to 256M to get manageable coredumps. After my troubles were resolved I removed that entry from my loader.conf. So this time my dump consisted of 1.5GB as did several re(4) related coredumps prior to my setting hw.physmem. I assume that the swap space isn't zero'd or otherwise initialized prior to a page being written to it. I also assume that a coredump is written sparsely to disk so old data could remain across coredumps. I guess I'll read the code and see if I can learn a bit more rather than making assumptions. Joe > > I've googled similar bug reports on FreeBSD, Linux, NetBSD, etc. I > have not found much information other then this: > > http://lists.freebsd.org/pipermail/freebsd-bugs/2003-September/003012.html > > Which seems to indicate that it might be DRM/DRI related.. or perhaps > just video/DRI related as this person triggered it simply by restarting > his X server a few times. > > BUT, our flush code already uses the changes made to FreeBSD, i.e. > uses ~(1 << 7), so I am somewhat at a loss. > > -Matt > Matthew Dillon > <[EMAIL PROTECTED]>
