On Fri, Jan 12, 2018 at 1:41 PM, Lepton Wu <ytht.net@xxxxxxxxx> wrote: > This finally resolve crash if loaded under qemu + haxm. Haitao Shan pointed > out that the reason of that crash is that NX bit get set for page tables. > It seems we missed checking if _PAGE_NX is supported in kaiser_add_user_map > > Link: https://www.spinics.net/lists/kernel/msg2689835.html > > Signed-off-by: Lepton Wu <ytht.net@xxxxxxxxx> Reviewed-by: Guenter Roeck <groeck@xxxxxxxxxxxx> Hint: You might want to version your patches; otherwise it is difficult for the maintainer(s) to find the latest version. Note that the fix probably also applies to v4.9 as well as to older stable kernels. Guenter > --- > arch/x86/mm/kaiser.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c > index 6a7a77929a8c..8af98513d36c 100644 > --- a/arch/x86/mm/kaiser.c > +++ b/arch/x86/mm/kaiser.c > @@ -198,6 +198,8 @@ static int kaiser_add_user_map(const void *__start_addr, unsigned long size, > * requires that not to be #defined to 0): so mask it off here. > */ > flags &= ~_PAGE_GLOBAL; > + if (!(__supported_pte_mask & _PAGE_NX)) > + flags &= ~_PAGE_NX; > > for (; address < end_addr; address += PAGE_SIZE) { > target_address = get_pa_from_mapping(address); > -- > 2.16.0.rc1.238.g530d649a79-goog >