From: Konrad Rzeszutek Wilk Date: Mon, 26 Jan 2015 11:51:09 +0000 (+0100) Subject: x86: vcpu_destroy_pagetables() must not return -EINTR X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~3856 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=de4f284b3d7b47d3b9807f354552ecf3e0fff56b;p=xen.git x86: vcpu_destroy_pagetables() must not return -EINTR .. otherwise it has the side effect that: domain_relinquish_resources will stop and will return to user-space with -EINTR which it is not equipped to deal with that error code; or vcpu_reset - which will ignore it and convert the error to -ENOMEM.. The preemption mechanism we have for domain destruction is to return -EAGAIN (and then user-space calls the hypercall again) and as such we need to catch the case of: domain_relinquish_resources ->vcpu_destroy_pagetables -> put_page_and_type_preemptible -> __put_page_type returns -EINTR and convert it to the proper type. For: XEN_DOMCTL_setvcpucontext -> vcpu_reset -> vcpu_destroy_pagetables we need to return -ERESTART otherwise we end up returning -ENOMEM. There are also other callers of vcpu_destroy_pagetables: arch_vcpu_reset (vcpu_reset) are: - hvm_s3_suspend (asserts on any return code), - vlapic_init_sipi_one (asserts on any return code), Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Jan Beulich --- diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 6e9c2c0a35..d4965da5e7 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -2677,7 +2677,11 @@ int vcpu_destroy_pagetables(struct vcpu *v) v->arch.cr3 = 0; - return rc; + /* + * put_page_and_type_preemptible() is liable to return -EINTR. The + * callers of us expect -ERESTART so convert it over. + */ + return rc != -EINTR ? rc : -ERESTART; } int new_guest_cr3(unsigned long mfn)