From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Igor Mammedov <imammedo@redhat.com>
Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com,
jeremy@goop.org
Subject: Re: [PATCH v2] xen: x86_32: do not enable iterrupts when returning from exception in interrupt context
Date: Thu, 1 Sep 2011 11:45:03 -0400 [thread overview]
Message-ID: <20110901154503.GA7626@dumpdata.com> (raw)
In-Reply-To: <1314877615-18280-1-git-send-email-imammedo@redhat.com>
On Thu, Sep 01, 2011 at 01:46:55PM +0200, 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 <imammedo@redhat.com>
> Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Stuck it in the queue for 3.1 and stable. Thanks for finding this one!
next prev parent reply other threads:[~2011-09-01 15:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20110829194633.GB16530@dumpdata.com>
2011-08-31 23:47 ` [PATCH] xen: x86_32: do not enable iterrupts when returning from exception in interrupt context Igor Mammedov
2011-08-31 22:37 ` Jeremy Fitzhardinge
2011-09-01 8:19 ` Igor Mammedov
2011-09-01 11:46 ` [PATCH v2] " Igor Mammedov
2011-09-01 15:45 ` Konrad Rzeszutek Wilk [this message]
2011-09-01 16:46 ` Jeremy Fitzhardinge
2011-09-02 8:18 ` Igor Mammedov
2011-09-02 13:40 ` [Xen-devel] " Konrad Rzeszutek Wilk
2011-09-02 14:01 ` Igor Mammedov
2011-09-02 14:47 ` Konrad Rzeszutek Wilk
2011-09-06 9:16 ` Igor Mammedov
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