From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Mammedov Subject: Re: [PATCH v2] xen: x86_32: do not enable iterrupts when returning from exception in interrupt context Date: Fri, 02 Sep 2011 10:18:23 +0200 Message-ID: <4E60914F.7080208@redhat.com> References: <4E5EB794.7050909@goop.org> <1314877615-18280-1-git-send-email-imammedo@redhat.com> <4E5FB700.1070908@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4E5FB700.1070908@goop.org> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Fitzhardinge Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com List-Id: xen-devel@lists.xenproject.org On 09/01/2011 06:46 PM, Jeremy Fitzhardinge wrote: > On 09/01/2011 04:46 AM, Igor Mammedov wrote: >> If vmalloc page_fault happens inside of interrupt handler with interrupts >> disabled then on exit path from exception handler when there is no pending >> interrupts, the following code (arch/x86/xen/xen-asm_32.S:112): >> >> cmpw $0x0001, XEN_vcpu_info_pending(%eax) >> sete XEN_vcpu_info_mask(%eax) >> >> will enable interrupts even if they has been previously disabled according to >> eflags from the bounce frame (arch/x86/xen/xen-asm_32.S:99) >> >> testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp) >> setz XEN_vcpu_info_mask(%eax) >> >> Solution is in setting XEN_vcpu_info_mask only when it should be set >> according to >> cmpw $0x0001, XEN_vcpu_info_pending(%eax) >> but not clearing it if there isn't any pending events. >> >> Reproducer for bug is attached to RHBZ 707552 >> >> Signed-off-by: Igor Mammedov >> Signed-off-by: Jeremy Fitzhardinge > > One nit, this should be acked-by or reviewed-by, not signed-off-by, > since the patch isn't passing through my hands. > > J I'm new to this stuff, would you like me to re-post it? Next time will do it right. ------- Thanks, Igor