Re: [PATCH v3 0/2] MR3566: server: Store both contexts in pending context object.

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about server/thread.c:
> -
>        if (is_pending || !thread->context->regs[CTX_WOW].machine)
> -
>        {
> -
>            context_t *ctx = &thread->context->regs[CTX_NATIVE];
> -
>            flags = contexts[CTX_NATIVE].flags & ~native_flags;
> -
>            copy_context( ctx, &contexts[CTX_NATIVE], flags );
> -
>            ctx->flags |= flags;
>        }
> -
>        flags = context->flags;
> -
>        if (native_flags && ctx != CTX_NATIVE) /* some regs are always set from the native context */
> -
>        if (is_pending || (ctx_count == 2 && thread->context->regs[CTX_WOW].machine))
>        {
> -
>            copy_context( &thread->context->regs[CTX_NATIVE], &contexts[CTX_NATIVE], native_flags );
> -
>            thread->context->regs[CTX_NATIVE].flags |= native_flags;
> -
>            flags &= ~native_flags;
> -
>            context_t *ctx = &thread->context->regs[CTX_WOW];
> -
>            flags = contexts[CTX_WOW].flags & ~native_flags;

If `ctx_count == 1`, then `contexts[CTX_WOW]` does not exist.

This happens when a 64-bit (native) process calls `NtSetContextThread` on a 32-bit (WoW64) thread whose context is still pending. In this case, `is_pending` will be true but `ctx_count == 1`.