On Sun, Nov 18, 2012 at 2:09 AM, Goswin von Brederlow <goswin-...@web.de> wrote: > On Sat, Nov 17, 2012 at 10:58:17PM +0300, Max Filippov wrote: >> On Sat, Nov 17, 2012 at 9:50 PM, Goswin von Brederlow <goswin-...@web.de> >> wrote:
[...] >> (gdb) b *0x100000 >> Breakpoint 1 at 0x100000 >> (gdb) c >> Continuing. > > That works, but only for addresses BEFORE where it crashes. What works, but > in no way helps (see below), it setting the breakpoint before the last > instruction and then "stepi". > > Only way that would help would be entering the monitor mode on such an error. Ok, I think I can cook a patch for that, but how are you going to use it? The issue is not reproducible with mainline qemu, neither current nor v1.1.0 [...] >> Looks like PAE support is broken. > > Yeah, any memory read just returns all zeroes. That threw me too. I had > to debug this by adding "mov $0x101000,%ebx" type instructions and then > check the contents of ebx on crash. I wagely remember this always being > broken. > > My assumption would be that I'm setting up the gdt, paging, the page tables > and such and the debug mode already tries to use them while the cpu is > still in the original mode. So the two don't agree on what is where. There's a bug related to PAE in the debug interface, I've posted a patch that should fix that: https://lists.gnu.org/archive/html/qemu-devel/2012-11/msg01635.html -- Thanks. -- Max
