On Tue, Mar 14, 2017 at 08:56:27PM +0800, Peter Xu wrote: > The address of memory regions might overflow when something wrong > happened, like reported in: > > https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg02043.html > > For easier debugging, let's try to detect it. > > Reported-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk> > Signed-off-by: Peter Xu <pet...@redhat.com>
After a chat with Paolo, I think the following is a more general fix - fix info mtree to do 128 bit math and display more than 16 digits if necessary - add info about region visibility how much info is appropriate is arguable - after all we already have info mtree -f we probably should report if region is not visible at all, how about partially occluded ones? listing all windows is probably not needed - we have the -f flag for that. > --- > memory.c | 21 ++++++++++++++++----- > 1 file changed, 16 insertions(+), 5 deletions(-) > > diff --git a/memory.c b/memory.c > index 284894b..64b0a60 100644 > --- a/memory.c > +++ b/memory.c > @@ -2494,6 +2494,7 @@ static void mtree_print_mr(fprintf_function mon_printf, > void *f, > MemoryRegionListHead submr_print_queue; > const MemoryRegion *submr; > unsigned int i; > + hwaddr cur_start, cur_end; > > if (!mr) { > return; > @@ -2503,6 +2504,18 @@ static void mtree_print_mr(fprintf_function > mon_printf, void *f, > mon_printf(f, MTREE_INDENT); > } > > + cur_start = base + mr->addr; > + cur_end = cur_start + MR_SIZE(mr->size); > + > + /* > + * Try to detect overflow of memory region. This should never > + * happen normally. When it happens, we dump something to warn the > + * user who is observing this. > + */ > + if (cur_start < base || cur_end < cur_start) { > + mon_printf(f, "[DETECTED OVERFLOW!] "); > + } > + > if (mr->alias) { > MemoryRegionList *ml; > bool found = false; > @@ -2522,8 +2535,7 @@ static void mtree_print_mr(fprintf_function mon_printf, > void *f, > mon_printf(f, TARGET_FMT_plx "-" TARGET_FMT_plx > " (prio %d, %s): alias %s @%s " TARGET_FMT_plx > "-" TARGET_FMT_plx "%s\n", > - base + mr->addr, > - base + mr->addr + MR_SIZE(mr->size), > + cur_start, cur_end, > mr->priority, > memory_region_type((MemoryRegion *)mr), > memory_region_name(mr), > @@ -2534,8 +2546,7 @@ static void mtree_print_mr(fprintf_function mon_printf, > void *f, > } else { > mon_printf(f, > TARGET_FMT_plx "-" TARGET_FMT_plx " (prio %d, %s): > %s%s\n", > - base + mr->addr, > - base + mr->addr + MR_SIZE(mr->size), > + cur_start, cur_end, > mr->priority, > memory_region_type((MemoryRegion *)mr), > memory_region_name(mr), > @@ -2562,7 +2573,7 @@ static void mtree_print_mr(fprintf_function mon_printf, > void *f, > } > > QTAILQ_FOREACH(ml, &submr_print_queue, queue) { > - mtree_print_mr(mon_printf, f, ml->mr, level + 1, base + mr->addr, > + mtree_print_mr(mon_printf, f, ml->mr, level + 1, cur_start, > alias_print_queue); > } > > -- > 2.7.4