Re: [PATCH v1] memory: remove assert to avoid unnecessary coredump

[Yan Zhao]

On Tue, Mar 03, 2020 at 11:11:14AM +0800, Yi Sun wrote:
> It is too strict to use assert to make qemu coredump if
> the notification does not overlap with registered range.
> Skip it is fine enough.
> 
> During test, we found such a case for vhost net device:
>     memory_region_notify_one: entry->iova=0xfee00000, entry_end=0xfeffffff, 
> notifier->start=0xfef00000, notifier->end=0xffffffffffffffff
>
so for range from 0xfef00000 to 0xfefffff,  would notification for this
range get lost?

Thanks
Yan

> Skip this notification but not coredump makes everything
> work well.
> 
> Signed-off-by: Yi Sun <address@hidden>
> ---
>  memory.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/memory.c b/memory.c
> index 06484c2bff..62ad0f3377 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1921,12 +1921,11 @@ void memory_region_notify_one(IOMMUNotifier *notifier,
>       * Skip the notification if the notification does not overlap
>       * with registered range.
>       */
> -    if (notifier->start > entry_end || notifier->end < entry->iova) {
> +    if (notifier->start > entry_end || notifier->end < entry->iova ||
> +        entry->iova < notifier->start || entry_end > notifier->end) {
>          return;
>      }
>  
> -    assert(entry->iova >= notifier->start && entry_end <= notifier->end);
> -
>      if (entry->perm & IOMMU_RW) {
>          request_flags = IOMMU_NOTIFIER_MAP;
>      } else {
> -- 
> 2.15.1
>