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    SubjectRe: [PATCH v2] xen: x86_32: do not enable iterrupts when returning from exception in interrupt context
    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<imammedo@redhat.com>
    >> Signed-off-by: Jeremy Fitzhardinge<jeremy@goop.org>
    >
    > 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


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