On Mon, Aug 20, 2012 at 2:04 PM, John Baldwin <j...@freebsd.org> wrote: > On Saturday, August 18, 2012 2:29:26 pm Monthadar Al Jaberi wrote: >> Hi, >> >> I am wondering is there a reason for getting "Fatal trap 12: page >> fault while in kernel mode" "supervisor read, page not present" for an >> address used to be valid in kernel space? >> >> I dont really understand why I am getting this, I added a hardware >> watchpoint on the address, and when I got to the debuger I could read >> the memory content and dump for that address. But when I continue from >> the debugger I get the panic and now when I try to read the memory >> content I get *** error reading from address ce733000 ***. > > Whatever memory was there might have been unmapped? For example, > memory pointed to by I/O buffers (struct buf/bio) use transient > mappings that are only valid while an I/O request is in progress.
Thank you the for the reply, so if a struct gets freed will the page it was on get un-mapped, so that I cant dump it in debugger? Even VirtualBox debugger cant dump the memory giving "VERR_PAGE_TABLE_NOT_PRESENT: Reading memory at...". In my case it is a struct ieee80211_node which gets freed, but where does the page get unmaped? I tried doubling the memory in VirtualBox. br, > > -- > John Baldwin -- Monthadar Al Jaberi _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
